First ever blow out with my MIL... I'm ridiculously upset and I don't know what's going to happen from here

Jude
I've never had any problems with my MIL. She's nice enough and we get along fine. We're not bosom buddies by any means but we're not enemies either. Our relationship is just kind of there... Anyway, just recently her mother passed. She lived in NJ so my husband and his family (mom, dad, sister) all went up for the viewing and funeral (we live in Florida). His other sister lives in Korea and flew out to Jersey as well. I didn't go bc I can't travel, I'm 34 wks pregnant and also high risk, so I stayed with our 2 other kids. Well, the whole trip turned out to be a disaster bc of the wrong information and dates they were given from family members in jersey... My husband was only supposed to be gone for a day and a half, tops but they all wanted him to stay longer (we're talking going on 5 days)... He didn't want to. He had a hard enough time leaving me in my state (not only ready to pop but I also had a tooth infection. I put my emergency extraction on hold so he could go to jersey bc he didn't want me to go while he was gone, in fear of my going into early labor due to stress)... His mother gave him a hard time for wanting to leave earlier than the rest of them but he wanted to get home to me. This is where I think it all started. He was up there for 3 days, spending time with his family (including his sister that came from Korea)... Anyway, he came home, then his family came home 2 days later... His sister from Korea was here for an entire week but she never contacted him to go out or spend time together... My husband is a busy man... We both work full time and both of our kids are in pretty demanding sports (not to mention, he coaches one)... Well, his sister's stay has come to an end... He didn't get to see her once even tho he called to see what she was doing (most of the time it was sleeping)... Well, his mother confronted me today at work (we work together in a family business) and tore into me saying that I keep him from his family. I'm a "selfish fucking person" bc never once did "I" pick up a phone to invite his sister out or try to get together... Apparently I keep him from doing things with his family, etc etc... Then she had the nerve to bring up my sister and how when she visits (from Austria) that I go out with her and do what I want. (Which is completely incomparable bc my sister stays with us when she visits) I felt completely blindsided. I couldn't get in a word edgewise... I told her that her son is a grown ass man that makes his own decisions, it had nothing to do with me that he didn't get to spend time with his sister... She didn't want to hear any of it, and then threw a "why don't you just go cry to your parents now"... Wtf?! She doesn't know shit about my family and I've only just begun to rebuild a relationship with my dad over the last yr, so that comment was totally bizarre and utterly rude. She pretty much ended with a "I don't have anything to say to you. You're just a selfish fucking person"
I don't know where to go from here. I've never disrespected her or her family. I get upset from time to time but keep it to myself bc she tries to treat my husband like he's still 5... He's tried to put her in her place but she's feisty. (They're Puerto Rican. Pretty traditional and very stubborn)... I'm about to have their first grandson (our other two kids are from a previous marriage) and I don't even want to have a relationship with her at this point. I've never been spoken to like that and I don't want to get pulled into family drama but nobody disrespects me (and at work of all places. How inappropriate!) I'm just kind of done. I don't need this stress or drama. I didn't do anything wrong... 
What do I do?! I'm angry, hurt and confused...