5 weeks and scared of miscarriage

I'm nearly 5wks and I am so scared I'm going to miscarriage. I have one son and didn't have any problems until the very end of that pregnancy. But with this one I wanted another child so badly and it took nearly 2 years of trying to conceive. I have almost no pregnancy symptoms. Only minimal breast sensitivity and some cervical soreness. Am I worried over nothing? Is there anything I should keep an eye out for?