Difficulty learning

I can't concentrate on learning for the passed year and a half (my gcse course) I have literally learnt nothing I'm trying to focus on what the teachers Are trying to teach me but I just don't get it and it doesn't stay in my head and and I just get distracted by little things and then my mind thinks of something else and I just jump from thought to thought and before I know it class is over and I haven't learnt ****. It's so depressing and makes me feel worse than I already do, also reading is really hard I jumble sentences and words and what I'm reading never stays in my head like even if I read it like six times i still don't understand what's going on, I also feel really bad because my teachers teach good and everyone else seems to get it but I just don't, I'm constantly confused and unaware of what is being taught. I don't know what to do, I told my mother and she said I was making it up which made me cry because I'm really not and I really want to stop being so dumb but no ones helping me, please if you understand what's wrong tell me

Did anything happen to you in the last year and a half? Did you have difficulties before this? It could be that the class isn't interesting to you. If you think it's something more serious such as a LD or AD/HD, I would see if your school has a counseling center or a learning specialist. They might be able to evaluate you. If they aren't, then they might at least be able to give you some studying techniques or tips on how to approach the class differently.