Why does this seem to happen whenever I get my period?

I get sick a lot,mostly headcolds and stuff.but I noticed lately,that when I get what seems like a cold,I get my period at the same time.I've had a sore/rough throat for the past few days,a nurse looked at it and said my throat was bright red.I've also been congested for a few days as well.Today I started my period again.Why do I get these colds and my period at the same time? D: