Immune system!

Laura • Im 24 years old been married and divorce already i have a daughter
Im 6 weeks and 3 days pregnant. And this is my third pregancy every time im pregant my immune system like shuts down i am on my 3rd illness since i have been pregant and normally i never get sick. I had strep an ear infection and now i have a cold..... Does any one else go threw this at all???