I'll try to answer your questions in order, but I think they are connected:

1) The way you describe what has been happening between you and your mother, you make it sound like it is mostly your fault. I also notice you don't mention anyone else...no brothers, sisters, father... in any case, since you and your mum have already got things a bit more settled there are 2 problems: first, how do you prevent it from starting up again; second, how do you stop beating yourself up about something you have handled pretty well.

You need to figure out what purpose the fights were serving. That's not the same as "why". When members of a family start acting differently it normally means something is threatening to break the family apart, and family members are struggling with it, wanting things to be the way they used to be. Even if the way things used to be wasn't too good, it was familiar and everyone knew where they stood and what to expect. It is often disruptive when things change; and it is even harder if things change for the worse. There is lots of blaming, self-blaming and friction until everyone comes to terms with the way things are going to be.

So, sort out what those arguments were achieving and figure out a more constructive way to get there before you have to. Were you making mum feel bad because she failed to do (or prevent) something? Or were you distracting her from thinking about something worse? Or making her angry or upset over something you could control a bit instead of letting her discover something wose that maybe she wasn't going to be able to handle? I don't know, and maybe you don't either, but you are in a better position to figure it out than me.

Figuring this out and having a go at a better approach will help you feel OK about yourself. It is harder to feel bad about yourself when you start to see reasons for what was going on and even harder to feel bad when you start to put your energy into something more constructive. Time helps, too. The longer you go without falling back into that angry pattern, the better you will feel.

2) Marijuana makes a lot of people feel relaxed and cool. Most people feel that way when they first start using it. But a lot of people eventually start getting anxious and paranoid, and it affects some people like that from the start. The 3 commonest reasons for the paranoia are chronic intoxication, withdrawal and early mental illness.

Let's take the last one first: about 1 person in 50 will have a major mental problem which usually starts to show up when they are around 18 years old. These illnesses need to be controlled with medication. If they have these sorts of illness, regular pot users start to show the symptoms earlier...by about age 15...paranoid ideas, ultra-suspicious thoughts, problems with their moods and temper, difficultly in solving problems and concentrating, odd beliefs, like believing the TV or music or news has a special message for them.

Now, this is NOT the most likely reason for what you have been going through, but it is possible. You need to STOP using marijuana immediately if this is the source of your problems, otherwise you will have a very hard time getting control of the illness, and treatment will not be nearly as helpful. If you quit using and the paranoia is still there in 6 weeks time, you should see a doctor and explain the symptoms (and your drug use) to them.

Withdrawal is a more likely cause of your symptoms. If you smoke heavily, or use more than 3 times a week for long enough, you body starts to adapt to the THC in marijuana. If you mix tobacco with it, the chance of addiction is even higher. If you then go long enough without using, for your body starts drying out, and you will have "withdrawals" that make you anxious, suspicious, super-sensitive and restless. Small things annoy you and you over-react to things. You sleep poorly and maybe have bad dreams, depressed thoughts and guilt.

The way to deal with this is to cut back on how often you use (no more than once, maybe twice a week) and how much you use. Actually, at 15 you shouldn't be using at all, because your nervous system has not yet matured, which means marijuana can slow down your development and also cause really long term changes to your brain and nerve cells. People who use marijuana regularly in their early to mid teens are 3 times more likely to have mental problems (like depression and anxiety) when they reach their 20s and 5 times more likely to be suicidal.

Finally, chronic intoxication is something that happens to regular users because a lot of the THC from marijuana gets absorbed into the fatty tissues in your body and builds up and up. Then, when you don't use for a while, it gets released back into your bloodstream, up to six months after you quit if you are a really heavy user! Then, even though you don't feel high, you are still being affected; your concentration isn't so good, your reaction times are down, you feel a bit lethargic, you get moods, you feel a bit useless and can't really be bothered doing things, which gets you in dutch with friends, parents, teachers. You also need a lot more marijuana before it relaxes you, because you are already partially stoned before you start.

These are three possible reasons for your bad experiences with marijuana, and maybe they have something to do with the bad vibes with your mum. And here is a solution: you need to cut way down. Maybe take a "drug holiday" where you use nothing for a couple of months. The best thing would be to consider quitting altogether. Sorry.

3) No, nothing you think of when you are high is more likely to be true than what you think of when you are not high, and a lot of what you think and feel and experience when you are high is rubbish.