Fresh water such as is found in lakes and streams can sometimes be contaminated by various bacteria and parasites. Probably the biggest concern from drinking unpurified water in this setting would be an infection with Giardia, which is a type of microscopic parasite that gets into the water from the feces of various wild animals. Giardia infection is characterized by bloating and cramping as well as periodic bad smelling bowel movements.
Although it is possible to get Giardia from swallowing just a small amount of water that is contaminated, I think the overall chance that the water you swallowed was contaminated is still pretty low. Therefore, as long as you are feeling well and continue to feel well you probably don't have to do anything.
If you develop abdominal pain
, diarrhea, fever
, chills, or other concerning symptoms then you should definitely go see your primary care doctor
. You should tell them about your camping trip so that they are aware of potential exposures, including to Giardia. There are simple stool tests that can be performed to look for Giardia, and the treatments for Giardia are medications that are safe, effective, and generally with only minimal side effects.