How do I deal with an envious mother?

My mother is extremely envious of me! I am 30 years old and retired from the military due to my disability. My mother is constantly making comments about how envious she is of people who are retired. She is getting really nasty...she makes rude comments about me getting old. I am confident and comfortable, I am proud to be in my thirties :) I took her out to eat and she said I have old hands. I recently purchased a house and she lives in an apartment. My mom always talks about wanting to buy a house. Everytime she visits me, she says I'm the only one who drops by to see you...you don't have anyone. I am tired of her being nasty!!! I recently relocated from a different state, and I will make more friends in this state. She went to the dealership two days ago, and there was a gentleman there who asked her if she has a daughter in her thirties. My mom said she started to show him my picture, but she changed her mind. My mom is in her mid-fifties and single. There are plenty of women her age married or in a relationship. I know my mom does not want me to be happy. She said the guy was really funny and handsome, but she didn't know if she could handle him. I thought that was awful...she wouldn't be the one in a friendship or relationship with him or maybe she was interested in him. She may have been upset that he asked if she had a daughter his age...maybe he was interested but he thought she was too old. I try to give my mom the benefit of the doubt, but she has consistently proven to be nasty and envious. I'm trying to distance myself from her...does anyone have any advice?