I see from your other threads that you are in the UK, so I am not as familiar with what might be available to you, since I am in the USA. You may need to do some hunting around to find where you can get the emotional support that you need. Decide that you are worth this effort. You are.

Your problems didn't start with the relationship with your brother. Something was very wrong before that, which made you vulnerable to getting used by him in that way. But the experience with him made things a lot worse. There has probably been a problem with you getting isolated that goes way back. It's very hard to overcome, but the sooner you start, the better your chances of getting on track toward a brighter future.