I'm in my first trimester of pregnancy and i just experienced some diarrhea, is that a concern?

Not likely: Diarrhea if severe certainly can cause some dehydration, but in general most diarrhea is self limited and responds well to over the counter medication. I tell my OB patients they can use some immodium (generic is fine) or kaopectate (kaolin and pectin) and to stay well hydrated.

Diarrhea : It is not fun to have diarrhea but it should be handled different because you are pregnant. If it continues see a primary care doctor for evaluation.