Why don't my parents appreciate me?

im 17 and dropped out of college for my mum (who has severe depression) to help round the house and with my two younger siblings but since i was 12 my parents don't really really appreciate what i do through school (yr7-yr11) i was horribly bullied and told to kill my self which i thought about but never tried but i all my parents did was tell me don't be so soft beat them up stand up to them etc... but then it got worse particularly since i started dating my fiance two years ago although they approve they just go over the top if i want to spend a moment with him i go out for a day come back to yelling told how lazy i am and do nothing for anyone today got worse my parents went out with my younger sibling so i cleaned the whole house changed there bed sheets did dishes etc... then sat down 3 hours later with a cup of tea then put the cup in the sink, then when they got back mum went over the top shouting how lazy i am for leaving one cup and because i forgotten to hang out the washing all my family is like that so the only person i can turn to is my fiance but he said live with him but i cant leave mum on her own what should i do im starting to feel worthless and so down any advice????