Baby fever-why? Long

My 4month old felt warm to me today at the store and when we got him home at dinner I felt him again and he felt warm. We took his temperature rectally and it came out 100.1 I know it’s not a ‘true’ fever until 100.3+

Still I’m a FTM and have bad anxiety so I’m beating myself up and feeling nervous!

We went swimming yesterday at family’s house in the shade but we were in there for about an hour. I don’t know if this could be why.

Since yesterday before swimming and today he wakes from naps and within 10 minutes he’s yawning and rubbing his eyes a bunch.

Breathing is fine no coughing or sneezing out of the ordinary. He’s peeing like normal.

For the past two weeks or so his eating has been driving me crazy! During the day it’s a huge struggle to get him to eat 1oz but at nap time when he’s very drowsy he will eat about 2-4oz and bedtime he will eat about 6-8oz and then about 4-6oz for a night feeding. I don’t know if he’s too busy during the day or what but we have to like fight him to eat and it end up all over him anyway. He gets breastmilk in bottles.

I’m so nervous I don’t want to sleep I just want to check his temperature again and have it be back to normal.

He has his 4 month check up this week but I want the dr to see him ASAP like tomorrow just to get peace of mind.

I feel like a horrible mom because this high temperature came out of nowhere😩