Congratulations on getting clean and sober!
The environment we are brought up in shapes our personalities, and can have adverse impacts on us later in life. Moving and changing schools was the only constant in my life, and making friends was a struggle. So I understand where you've come from. Bullying also has a strong impact on our self worth and self esteem. The thing with bullying is that it's a reflection of the bully not the victim, but after a time of being exposed it's easier to convince yourself that you're the one with the issues.
In terms of why you're bothering, there are 2 people you have to do this for. Yourself most importantly, and your deceased friend. There is so much you still have to live for and look forward to. Your friend convinced you to seek help because she knew how difficult it is to struggle alone. If she is looking down on you now, she would be saying the same thing.
Are you working at the moment?
Perhaps this effort you've taken to reach out for support can be your turning point. If you're not already doing so, then I'd look at seeing a Psychologist. You are worthy of this professional help. Talking through your thoughts and feelings with someone is a good place to start.
Once you start to rebuild a bit of confidence then start looking at some ways to meet people. Perhaps join a gym class, a book club, a support group, a sporting club, an art class, or something else you have even a slight interest in.
Do you want a family of your own? Once you start meeting people and socialising a bit more, maybe you want to focus your attention on meeting someone special.
I know you mentioned you left school, perhaps going back and doing some studies might give you a sense of purpose and achievement, and even open doors for alternate career prospects.
The thing is we have to work on one thing at a time, otherwise it looks so overwhelming. You might also like to check out some techniques for improving your self worth and self esteem in the interim. Using some affirmations, doing one pleasurable activity per day, writing down at least one thing you are grateful for each day, pampering yourself etc.
I'd also say be true to who you are. If you're wearing a mask of happiness or perfection this can be really exhausting. Your efforts a better spent on letting others see the real you. That's what people look for in others, genenuity.
We are all here for you. I hope you will get back to us.