Being judged

I'm really tired of feeling like I need to defend myself to everyone. I'm 22, I'm doing all I can to take care of myself and my family and get through school, I've been through hell and I don't feel like I owe anyone any explanations anymore. There's something about grief and loneliness that can make your heart turn cold sometimes, I don't have any patience for overly judgmental people who look at my life like I need their advice, then do nothing but criticize me.
Sometimes I really want to tell my boyfriends brother that the reason I don't come to family parties or to hang out during the week is because I can't stand feeling like everything I do is being judged and criticized by him. I've had people like that around me my whole life, and the one consistent thing is that I get away from them as quickly as I can. I dislike people who look down on others, having been homeless and/or poor at various stages in my life I know how it is to feel like trash and I can't stand people who are constantly looking to judge others as a way of feeling superior. I told my boyfriend the other night I don't care if my family comes from the gutter, if you come into our home we would treat you with respect and not ridicule you and make you feel stupid, we might be poor but goddamnit we have manners.
More and more I'm just angry and I need to bite my tongue because I can get pretty vicious verbally when I'm angry like this, but at the same time I need to make it clear that I'm not going to just stand by and be insulted anymore, I waited for 5 years for my boyfriend to stand up for me and obviously he won't, so that means I need to find a tactful way to say, "either respect me and treat me with at least as much civility as you would a stranger, or get out of my house and don't come back".
I don't see how asking someone to not inspect my housekeeping and laugh in my face in my own living room in front of a room full of guests is too much to ask, but I feel like I have to defend myself for expecting respect. Maybe I am too sensitive,  but so what? If someone is obviously hurt by your "jokes" you should back off, that's pretty basic manners where I come from.
Sometimes I don't know how much more of this I can take.