5.5 weeks pregnant, Brown blood and I’m worried! Please help!

Rachael

Hi, I recently found out we were pregnant. Christmas evening I noticed some brown blood when I wipe, so I wiped deeper and I noticed it was dark brown with one or two blackish stringy bits. I have been suffering from a digestive bug (I won’t give you the detailed) for about 2 days and Xmas morning we had sex. Could that be the cause? Is this normal in your first trimester? If so why is it happening and what can I do? Please help, I’m trying not to worry, but I am 😞☹️🥺