My dog has been throwing up off and on since Monday, but not a lot and mostly watery. She also started drinking noticeably more, and typically vomits a little after drinking a large amount of water, but otherwise she is acting normal and energetic as usual, which is why I haven't had any cause for concern, shes also eating normally and doesn't vomit the food. She had all her shots (rabbies, distemper/parvo, corona) done about two weeks ago. Is this a possible side effect? Or would that have occurred sooner?

If you were vomiting water since Monday would you be worried?  Probably...safest bet is to just take her in.  Sucks you waited until now, if you have to go to the pet emergency room it's fucking expensive, a lot more than a normal vet bill would have been yesterday...

She isn't lethargic or otherwise showing any other symptom of sickness, in fact shes energetic and playful as always. And its not constant, she maybe did it twice on Monday, then was fine until Thursday and vomited a small amount, then tonight she vomited again, so now I'm starting to get a little concerned.

Since Monday? Get her to the vet!

ETA: okay, so it's off and on. I hadn't downloaded your most recent post. Not as bad, but still: vet in the morning.

Got her to the vet this morning and they said vomiting is due to her water drinking, but the reason she started drinking more was because of a condition developing in her uterus. They had xrays done and she has signs of early Metritis. Vet took blood & urine and gave her antibiotic injections to relieve the condition for now, I wont find out until Monday the results of the tests. I'm going to have to get her spayed sometime this week to prevent it from becoming a bigger problem.

Sorry about your pup, glad you got a diagnosis and a solution.