Feeling run down...

Why is it that as soon as I find out I am pregnant I get a cold!! This happened last time too. I am not one who generally just lives through a cold or any other illness. I am proactive at getting rid of it. I take medicine and get rid of it. Unfortunately I can't take medicines in my first trimester (at least not enough to do any good). I hate being sick and knowing that I have to just suffer through is very aggravating. I am however looking forward to the 3-day weekend. lots of recouping time.