Too hot?

Helen
I'm 4+5 weeks and worried about how I had fevers from a sinus infection at 2 weeks and lots of sun/heat on vacation last week. I've read that one should avoid getting your temp above 102, especially during the first 3 months. Is that because of risk of miscarriage? Would I have already had one by now? Are there other risks? Should I be worried? 
​I'm going to make an OB a appointment but understand the first isn't until around week 8. Appreciate your comments!