I had intercourse on th 5th of October, and I had an appointment on the 15th of October for a follow up from an abortion (please don't judge, I have my own personal reason why I did it). On the follow up they did a urine test and said it was negative and they prescribed me my first birth control pills. I started taking them on the 20th of October. I had no side effects yet but last night I vomit some of my food 2-3hrs later after I took the pill. So I was wondering if it's the birth control pill side effects or is it that I am pregnant? Is the pregnancy test I had taken accurate?

If you aborted then you're not pregnant. Unless you got pregnant again after your abortion.

My take on your post, they tested too early after your abortion and after sex (I'm assuming it was protected, seeing as you obviously don't want a pregnancy) to determine if you're pregnant again.

Vomiting can happen for many reasons, pregnancy being the least of them. You could be reacting to medication, you could be ill.

There's really no way to give you an answer to your question, since there are so many possibilities for the symptoms you're having.