5 month pregnant and always sick

Hi everyone, I'm 5 1/2 months pregnant, and have been sick what feels like the entire time. Not nauseous and vomitting, but cold and flu like sick. I've already been to the doctor, got put on an antibiotic and was told what I'm able to take medicine wise that's safe during pregnancy. Everything is going great with the baby, baby's looking healthy and it's been an easy pregnancy. Just that I'm sick all the time. Before I was pregnant I was NEVER sick, very rarely would I even have a cold, and now this is my 3rd time in 5 months being actually sick enough to call out of work. Has anyone else experienced this?