The anger and frustration you are experiencing is indeed part of the process, and it's a good sign in itself. However, some people sit in this state permamently because, as much as they hate it, they convince themselves that they have no control, lack willpower etc. Quitting can be as easy as just stopping, or it can be an extended process of stopping, starting, stopping, starting... Regardless, the important thing is not to beat up on yourself for it. Regardless of how bad you feel, don't con yourself into thinking you can't quit, cause then you really will be defeated by it.
Some people advocate cutting down, but I personally believe in going cold turkey. How tough are you? How fed up are you? Seeing as you've finished university, I'm assuming you've been through difficult and stresfull periods that a lot of other people would freak out at, so I'd assume you're definitely strong enough to do this. A no tolerance approach is the fastest and most direct way of quitting. If you wanna give it a go, this is what I'd recommend: take a few deep breaths, then throw out your stash, throw out your bong, pipe and all your implements, delete your dealer's phone number, stop hanging out with your weed smoking friends for a while, don't replace weed with booze, and don't set yourself up for any other significant challenges. Pay close attention to your anger, as you'll probably become quite cranky, but try to remember that it's the withdrawls more than it is the people that are annoying you. Accept the fact that you might have bad dreams, trouble sleeping, sweats, loss of appetite, clumsiness, and trouble staying focussed on things - this is all temporary. Eat and drink food that you enjoy, but try not to eat too much junk food (I did a lot of smoothies - easy to get down and filling). Drink lemon water and eat brown rice and fruit to help detox your system. Do things you enjoy, even compulsively if you have to, but try not to watch too much TV. If you sit passively in front of a screen for too long, you may notice a stronger urge to use after you turn it off. Try to stay interested in things - keep reading, using the computer, doing hobbies you enjoy etc. When you have thoughts about using again, tell them "NO!" Don't entertain them or you will pick up. Be good company to yourself. Tell yourself that you're a good person, for no other reason other than it makes you feel good. Don't entertain any self-deprecating thoughts - they will only work against you and make quitting harder. If you try and surround yourself with people as a distraction, you will probably feel more lonely than if you kept focussed on yourself. Tell your parents if you want to, but only if you think they'll be supportive. Don't bother telling/talking to anyone who is not going to say positive things about it - they'll just make it harder. But do tell someone, even if it's just people here - don't do it completely alone.
After a few days you'll feel brighter and clearer. After a week it'll get a bit easier. Then after two weeks it'll get easier again, and so on. Be prepared for hard moments though. There will be times that you want to give up, and there will be times when it just feels too hard. Remember, these are just feelings, they're not reality. It's not too hard, and nvever will be. Always remember that, as bad as you feel, this is as bad as it can get WITHOUT drugs. Inevitably, going back to using will make you feel worse, either in the short or long term. So, when you feel really bad, try and step back and remember that this is it, this is as bad as it can get, it's not going to get any worse than this, so you can still deal with it.
After the initial phase is over, you won't feel the desire to use as much, but you will still have challenges. The main one is learning new coping mechanisms, or relearning old ones. Weed has been something for you to fall back on in times of stress. You won't have that anymore, so you'll have to work at new strategies for dealing with things - this is part of the longer process though, and not immedietely relevant. Just remember that, if you feel like you can't cope with life without weed, it just means you have to find new ways of coping. Everyone has to do this, not just drug users. In reality, everyone has good days and bad days, so when you have a bad day, remember that straight people have them too, and they don't go home and smoke weed to deal with it. Pain is a part of life, so remember the following:
Q: Do drug-dependent people have a "chicken" attitude to pain?
A: Only the ones who continue to use.
The fear and anxiety only lessens after you stop. It won't be too long before you're dealing with things much easier than you did when you were smoking, and you'll feel stronger and more capable of dealing with life. Good luck. You can do it, I know you can.
And if you should relapse, remember that a relapse does not reset the clock. You don't have to go back and start counting from day 1. For every day that you are clean you are building up time and getting better at it. One moment of indescretion won't ruin all the work that you've done up to that point. If you relapse, remember to re-establish your priorities before you go to sleep that night, and pick up with the abstinence plan as soon as you wake up the next day.
It's a workable plan, trust me.