Potty training regression!

Casey
Anyone have any advice on this! Our son is 3.5 and has been diaper free (except for poop) since 3rd birthday. He's always done great, we never pressured him, and made training very easy. Lately within the past 3 weeks he's been peeing his pants sooooooo much. He used to jump up and run to bathroom when he would feel like he had to go really bad, but now he doesn't even say I peed my pants I only know because I'll feel him or see it's wet. I'm so stressed and have no clue what to do, I don't want to just put him back in a diaper all the time.....any advice is appreciated. He still asks to a diaper to poop which is fine I know not to push it, we ask him to sit sometimes he will try most often he says no, but pee has NEVER been an issue. My inlaws and sometjems DH push him about poop and the other day my MIL came over my 19 month old was asleep on top of me and my 3.5 had pooped in his diaper and she wouldn't change him. She said your a man your to big to be changed! I was so pissed... Anyway now maybe could the pressure from others making him regress? Or is he just distracted and to busy?