Don't worry. The brown discharge is your vagina eco system (the bacterias insides) adjusting to new intrusion (your bf batang). Is this the first time you have intercourse?

Ask yourself this few question.
- Any change in eating habit?
- Are you eating well?
- Any change in sleeping habit?
- Any stress factor?
- Any new stress taken? (ie. new boss making ridiculous work demand)

If you have that could be the reason for the dizziness.

Anyway, pregnancy stress is simple. Just buy a few brand of test kit (to be safe). Then pee on it.

If test negative and you still have the symptoms, go see doctor. Chances are you are INFECTED or PREGNANT (sometimes early into pregnancy can't be detected).

If you are PREGNANT, congratulations. Your life is ruined. (Unless you abort, but that is your choice)

If you are INFECTED with garden variety STD, time to change boyfriend. Your life is ruined, temporary.

If you are INFECTED with AIDS. Though if it is AIDS, there won't be symptom so early on, but if he is HIV infected from multiple sex partner or from "chicken", then he might have other STD. Your life is ruined.