revision suggestions

hi guys, i left school when i was about 13 (year 9) for personal reasons and ive been learning from home since. i could really do with some websites, past tests etc. 

bbc bitesize isnt helping me much with anything atm, and i cant find anything online either. i struggle concentraiting on one set thing and i need something more where i can answer questions and whatnot. i have my gcses soon and im worried by every other day passing by. much appriectiated if anyone can help