Pushing boundaries

It’s been a really long tough day and I need to talk about it. My son has just turned 15 months and is pushing boundaries all day. Saying no doesn’t work which is fair, he’s still little so I have to physically remove him from the situation. That then leads to a full on meltdown with screaming and arms flapping. It’s been a full on day of he repeatedly doing things he probably shouldn’t. I’ve had to pick my battles and if I don’t want him doing it but it’s just an inconvenience not a safety thing then I have just let him do it (eg. splashing in the dogs water bowl) because I don’t have it in me today. I’m also 11 weeks pregnant so very hormonal and tired which isn’t helping but I just feel like I’m at my wits end with it. He’s also very tired today which I don’t think is helping either, I had to wake him up from his nap earlier because otherwise he wouldn’t sleep tonight. I feel bad saying it but I can’t wait for him to go to nursery tomorrow just so I can have a day where he’s not screaming at me. I feel so guilty that I’m struggling this much with it all at the moment