Sorry to hear about your struggles. Hope today finds you a little bit better.
As a mother, I am sure you did the right thing by telling your mum. She will be as concerned as you are, but possibly, like you, isn't sure how to help you.
Talking to people here is a great step. If your first psychologist didn't work for you, try a different one. You have a distinct personality and you have the right to talk to a pyschologist who relates to you. Have you been to a GP, or a Psychiatrist to see if medication is an option. I'm not saying it would be, but it is another option to consider.
I don't say these things lightly, and have a 19 yr old daughter who has been down this path, and for her, Cognitive Behaviour Therapy and medication helped a lot. It may not be the road for you, but it is worth looking into.
I glad that you have told some friends. That is good that you have people you can trust with this information.
If the weight is botheringy ou, ring and talk to the Butterfly Foundation. You don't say whether it is over eating or an eating disorder, but they have some useful fact sheets, and are not judgemental.
Try and remember that people like you for who you are: not what you look like or the illness you may have. ÝOu are not defined by your illness, although it may feel like it.
Keep the lines of communication open with your mum. She will be just as worried and confused as you are. Ring Lifeine is you need to talk and let mum know she can ring too. There are a lot of people out there who care and can offer to listen.