SOS. Toddler won’t sleep

Ladies, I need help. My son (23 months) has just learned how to get out of the crib and we are working on transitioning to a big boy bed. The problem is with all of this new found freedom, he won’t sleep!! The first night I sat in his room with him until midnight until he fell asleep, and last night he was up until 2 am and didn’t even want to go to sleep then!! I would be okay with him playing quietly or reading in his room until he fell asleep but he has so much fun he doesn’t want to sleep. I am 16 weeks pregnant with our second baby and I need sleep 😩 I tried everything last night, rubbing his back, reading books, taking him for a drive, being nice about telling him to lay down, being stern about telling him to lay down - nothing works. He just climbs out of bed and wants to do do absolutely anything else but sleep. I was in tears last night because I don’t know what else to do! I also can’t shut him in his room until he falls asleep because his bedroom door is a sliding barn door and he can open it from the inside. There’s not really a way to keep it from opening unless I put a latch on it, and at this point I’m considering it. 😂

Please help!!