Need Advice on my 2.5 year old

I am currently 35 weeks pregnant. My 2.5 year old is for sure going through a little bit of the terrible twos, but overall he really is a great kid. I know he is only 2.5, but it’s been so hard for me to not get really frustrated when he’s not listening to me. When he gets mad, he hits. This is the biggest issue for me. He gets told not to do it again and if he doesn’t listen he goes into time out. And at night, he stalls SO BAD at bed time. Our night time routine can take up to an hour or more! And I then feel so awful for being so frustrated. I don’t know if it’s because it’s harder for me to do things with my big belly or what. I could just cry about it sometimes... I always try and remain calm with him and not let me frustration show, but I know sometimes it can. Any advice would be great or just some support.