i am getting too pregnant to be doing this

I am getting to0 pregnant to be cleaning someone else's house other than my own and going for a hike in the woods right after. Actually I am not pregnant, I just need to go at a slower pace then I am use to and the up-down-up-down with cleaning gets to me after while especially hauling around a heavy vacuum up and down the stairs. My mom is having gum surgery on Friday and I wanted to clean her house for her so she would be able to relax and recover in a clean, neat house especially since next week is her spring break and she will be home all week. Since my sister got married and moved out my mom's house is a lot easier to clean because it is just her and the cats, but because of the cats there was a lot of cat hair to deal with. Not that my mom's house is dirty, but she doesn't have a lot of time to keep it immaculate and it can get hairy quite easily. After cleaning I picked up Lance from the shop and met a friend at the park where we took a little hike through the woods. I had to carry Lance part of the way because he was getting tired (it was close to naptime) and refused to walk. As a result of my cleaning and hiking I am tired. I feel like such a wuss for being tired, I don't want to be a total bum, but at the same time I don't want to overdo it and not have the energy to play with Lance this afternoon or abuse my body that is working hard.
I am currently enjoying naptime and I just glanced out the window and noticed it just started to rain. It has been threatening rain all day, but I was hoping it would hold off until this evening. I know that Lance will want to play outside when he gets up from nap and I really don't want to play in the rain. Maybe it will just quit soon and dry up by the time he gets up.