Can I get an answer please.

Well today I had a decafe latte from Starbucks and I literally had the worse stomach ache ever! I had bad diarrhea (sorry TMI) and when I went pee later on I wiped (my front) aNd I had a very small streak of pink blood. This is my first pregnancy and I'm 4 weeks and 4 days. Any thoughts, suggestions or calming advice? Lol.