Mother in law jealous of me😂😂

So I live with my fiance in his dads house. This weekend my fiance had gone to work and his dad and his girlfirned were outside drinking. When my fiance (Mike) went to worm Scott (Mikes Father) asked me to come up and have some margaritas with them. We were talking and drinking for a while When Scott said he would be right back he was going to go get some cigarettes. I was left with (Donna) Scott's girlfriend. She was shit faced. So I ask her how her and Scott were doing and and she looked at me calmy and said that she thinks he is loosing intrest. I told her I was sorry. Then out if now where she starts screaming at me saying it was my fault calling me a bitch and other names. I looked at her and Calmy said how is It my fault? (she doesn't live here by the way, but I do) I am Engaged to Scott's son Mike. Mind you I am 19 and Donna and scott are in their 50's. So she still screaming at me says your living here and I am not so Scott is always looking at you. Your always around him and your taking him away from me. I don't know if she is delusional or crazy. I don't even talk to Scott rarely. Why would I want him. Then she starts going off saying that I am always in a tank tops and shorts (it's summer) I live in the basement with Mike it's furnished and it has a kitchen and bathroom it's like a miny apartment down here.. Scott lives up stairs. So I am never upstairs. So when Scott got home from getting ciggs he hears her screaming at me calling me a bitch and this and that. He tells her to leave and she leaves he does not follow her and then Donna starts texting Scott saying how can you fit there with her and talk to her? Scott gets up and goes to her just to say "it's sad your jealous of her" Hahahahagaga I'm dead it was so funny.