Today he 3 months old with 38.5 temperature

Hope you can help me. .

First time that my baby with temperature, 38.5 sense evening.

I not sure what to do. He was happy before went to sleep not crying much. Nothing different but with temperature. .

Do I need to go to hospital, I'm breastfeeding, tomorrow morning I will definitely go to see my GP.

Please guide me and help. My second child 2.5 years also not well with runny nose, and choose.

Thanks a lot!