Pup mommas ?? Am I overreacting ?

I’ve been going through hell and back with my mother in law all because of my sweet pup.. She’s been living with my SO and I ever since his father left us the house . (He’s the youngest and she does NOT want to leave his side). I rescued my Snoop last year in August as my doctors told me it would help a lot with my depression as well as with my sons social skills ( he’s super shy and won’t be around anybody or kid). Everything’s been going amazing! This dog has helped my family out soooo much not only for my depression and my sons social problems but I’m also type 1 diabetic and he himself learned to warn me about my blood sugars 💙 the perfect rescue pup 💙 to shorten this up my MIL has been calling me disgusting and a bad mother for having him around while I’m due with my second child any day now . My first son was 1 yrs old when we rescued him . She constantly tells me that I’m choosing my dog over my kids just because I refuse to give him up over this witches opinions (imma just keep it nice) My dog has always been an indoor dog and he would only go outdoors to use the bathroom and get some exercise (he’s a super pampered shih tzu) the other day I ended up in the hospital due to my diabetes and I came home to my dog sitting in the yard THAT IS NOT FENCED without his collar or leash on with his cage, bed, food bowls and literally everything thrown around the yard . We live right by a highway so I thank GOD that he didn’t run !!

I spazzed out and screamed “WHO TF DID THIS SHIT?!?” This bitch quickly comes out saying she was trying to “clean” . I AM LIVID AND WANT THIS WITCH ASS OF A WOMAN OUTTT . My SO has told her that she has no say in what happens or stays in this house and she constantly states “I’m your mother! How can you talk to me like that ?” With her fake ass tears coming down . I feel like my only option is to leave our own home just because of this hag.. I don’t want to get rid of my dog nor put my family through anything but this lady has put me through enough. Honestly growing so much hate towards her and I don’t think it’s due to this pregnancy 🙄 What should I do ?? I feel bad because she’s the only parent my SO has now that his father’s in Mexico but I can’t deal with her anymore.. our bond use to be so strong and she’s ruined it over this .. and no . He is NOT just a dog .