It's not easy to get over a relationship. You go through all the stages of grief and still you hurt. In my experience only time really helps. That and making new, better memories. It's true that you need not take seriously what your mentally ill relatives say. Try to remember when that voice in your head says ugly things that it is the voice of your mentally ill mother, not the truth. You've never been given any healthy patterns to live your life by. You need direction and training to be able to function effectively in the world. If you can't get someone you know or your counselor to coach you then go online and start reading all the self help articles you can manage. If you can learn how to approach people properly and gain some friendships it will help fill the void left by your bf. PC is another place you come to for support and friendship. People here know how you feel and are almost always kind. there are social clubs for almost all interests and you can start one of your own if you want to.
Please consider getting a little training towards a trade or college. Being financially independent will make you feel more powerful. Go to you local college and see what is possible for you. If there is some short term training available with real job potential that would be ideal.
Maybe you could do some volunteer work. That always gives one a sense of worth. It's the best thing to help self esteem.
Pet would be wonderful like Sam2 says. Budgies are also great pets.
I hope you find some answers