4year old potty accidents?

so very recently (within the month) my 4 year old son has been having more accidents. he says because "he doesnt feel like going potty" so lately Ive been making him go to the bathroom with me everytime I go. He still ends up pooping/peeing his pants. When I ask him about it he just laughs at me. he knows its wrong and has been potty trained since he was 2. The only changes thats happened is he now has a baby sister (6 months old). We've been trying everything to get him to stop. Positive and negative discipline (Taking things away / Letting it slide but making him go the bathroom every 30 minutes) we've tried taking him and only him on a day to himself to do whatever he wanted with his dad and I but the next day he ends up doing it again and laughing at us. he has destroyed our couch due to constantly going to the bathroom on it. ive tried sitting down and having a real conversation about whats going on but he will scream at the top of his lungs, hit and tell me he hates me and wants me to die. I have no idea where any of this is coming from and Im unsure what to do at this point. he has a physical tomorrow with the doctor and im going to bring all this up to him for his opinion on it but is this normal for his age? I feel like a terrible mom, and im constantly crying over his words to me and him hitting me. I dont like spankings so we've only done time outs for 5 minutes and taking toys/tablet away everytime he does it.