I can understand how you are feeling and how ur mind must be asking for every question to be answered! I do the same everyday!
My mum was diagnosed with AD at the mear age of 56 and i was only 17 now im 22! so even though its been 5 years its still hard to see you mum change and not have the 'perfect' mum and more!
Do u live with ur grandparents now? I really hope you get through ur GCSE's, try not to let it affect how hard you work as im sure your mum would not want her to hold you back! It affeted my college and even though i did get into i could have done better!
If you ever want to chat just message me!!