What are some natural ways to strengthen immune system while pregnant i keep getting infections?

It started with UTI's and yeast one after the other right after the medication then it came out i had strep throat then a bladder infection with e coli now i think i have a cold and my throat feels raw. What can i do i am tired of medication i hate taking medication because i'm pregnant 14 weeks today and for most of the time i've been on some sort of antibiotic. Please help.