How do you deal with a petty sibling?

My sister and I are 4-years apart. She is very emotional and I have always been more logicial. We are both successful in our own right – I’m not sure how you measure that in life, but if we are going “on paper” I’m slightly ahead based solely on the fact that I am more independent, financially stable, married, etc. There are phases when our relationship is in a good place, but she is always hyper critical of me. Lately, it’s been pretty unbearable: She throws me dirty looks but won’t come out and tell me why she’s mad, she looks me up and down because I’ve gained 15 lbs and am dressed casually to family dinner, she’s always complained about the preferential treatment of my stepsiblings. Recently my job was downsized (after working 60+ hours/week for almost 10 years) and all she can do is make snarky comments. I don’t want to imply I’m perfect – often I’m short tempered, I don’t have a lot of patience, and I know I’m not always the girly sister she wants me to be. Does anyone out there have any advice?