My sisters boyfriend peed in her soda, I didn't know but I drank a little of the soda. He smokes weed and drinks, I don't know if he has any STD's. Is there anything I should be worried about?

Do you really think he has any diseases? If you are really worried he has STD's, make an appointment with a doctor for tests sometime within the next few months. Certain STDs don't show up immediately.
Frankly, I would be more worried about my sister. What kind of jerk pees into his girlfriend's soda? Tell her to get a boyfriend who treats her like a queen, not a toilet. I am truly sorry you were the recipient of his idiotic behavior.

Yes, boyfriend is childish and a jerk, she needs to leave him now.

Most likely will be OK, but if in doubt a doctor is never a bad idea.

First get him cheked out it does matter if he has something but the main fact is you still drunk somebodys pee and what makes it worst was it was a boys pee and yes she needs to leave him if he's going around peeing in soda... know if he do have something go to hospital. But I'm preety sure you knew that already..