4 year old “regressing”; due with second child soon

Without sounding super dramatic, I’m feeling like I’m drowning a bit. Excuse the novel.

I’m nearly 9 months pregnant in what has been a very long and high risk pregnancy. My son (4,3m), has been having a really tough time the past few months. I’ve been reading some posts on here, and it sounds like I’m not alone, so I feel a little bit (albeit, selfishly) better there.

My 4 year old has been a super easygoing, happy, chill kid since he was born. He has a minor expressive speech delay and a few sensory processing issues, but he’s made leaps and bounds in the past year. His receptive language has always been on par or above average. Anyway, he’s always been down for whatever and easy to please - up until recently.

These days he’s fighting me on literally everything. From basic things like sitting to eat a meal, to brushing his teeth, to going to bed at a reasonable hour without me or his dad in there with him for hours. To be honest, I know a lot of it (if not all of it) is my and my husband’s fault. Between insane work schedules and this pregnancy, we’ve gotten super lenient on his schedule. Too many nights of just letting him crash with us in bed, or skipping bath time, or all of us eating at different times due to us having to shift things around so much in our own schedules.

The issue is that I have no idea how to backtrack what I’ve done now. We’re big on gentle parenting, but every time I try to get him back into a routine, it’s a half to full on meltdown. I feel like all I’m doing is trying to save the situation 24/7. By the time I go to bed I’m so exhausted, and I’m truly wondering how I will be able to give him this same attention when we have a newborn here soon. I’m terrified I’m just going to make it worse.

The straw that broke the camel’s back, so to say, was last week after daycare. He’s in summer camp 3-4 days a week, and he loves it! He comes home everyday super happy. When I went to pick him up though, his summer teacher told me he has been holding his pee/poop all day for a few weeks now. Like ALL day. She’s been taking him to the bathroom every 2 hours, and while he used to just hang out on the potty when this first started, now he’s been getting upset with/fighting it. Before this regression, he had made great progress using the potty at daycare (just needed some minor assistance at times).

I have no idea what caused this. I have no idea how to fix this. Sometimes after daycare he’ll pee on the potty at home before bed, and sometimes he won’t. He still wears a pull-up to bed, and I have noticed him asking me to change it quite frequently as of late (like once if not occasionally twice before he’s ready to sleep if he has to pee and poop - all technically after his bedtime). He’s always had good bladder control, but I realize this is not at all a healthy or sustainable thing for a 4 year old. He knows how to potty, where to potty, he dislikes accidents…and all of that. So to me it’s baffling on next steps here.

If anyone has advice, pleaseeee 🙏. I feel like I’m going to totally fail him when this baby is here if we keep going down this path (or lose my own mind lol). I’m also worried he’s just going to keep regressing. Just today he was fighting me on going to the potty before dinner. Like 1-2 of these things make sense as a typical phase for his age, but I feel like it’s all happening at ONCE.

We do our absolute best to keep our household stress free and positive when he’s around us, so I truly cannot figure out what’s going on. TIA.