Need help...

My son is 3years old and is so bossy, he says things to me like 'get your pyjamas on now and get into bed' when i say no to going to bed with him and when he gets really angry he punches me and bites etc etc. I'm not sure what to do anymore, i've been searching the internet for tips but cannot find anything he jsut won't take no as an answer, i don't give up but were up nearly all night every night with the same battles then again in the morning i have a battle to get him to eat breakfast because he wants sweets instead. i'm so exhausted if anyone has any tips please let me no. I am a single mum so have no help.