Birth control pill as morning after pill, dangerous to fetus

i took the pill also but mine was 24 hours after. i also got the brown discharge as my period. the lady said i will get my period in 2 weeks. i got it in less than a week. i dont know if that was normal or not. the nausaed is a side affect of the morning after pill but it usually doesnt happen. if you are pregnant, the morning after pill has no affect on the fetus. none what so ever. i was also wondering why i got the brown discharge afterwards. i think it might be from the pill because i am not on my period as normally would be. blood. therefore i am not pregnant. the brown discharge as my period is still unknown.? any help also?

I'm quite embarassed because I think I've done something stupid.

I'm 24 years old and have been taking birth control for a few years. two weeks ago, at the end of my period, my husband and I had unprotected sex without thinking about it. (I didn't restart my usual birth control cycle, because I decided for other reasons I wanted to see my gynecologist about changing methods.)

Four days later (about 96 hours after intercourse), I started panicking, and I took two birth control pills; the next morning I took two more. I've use the "morning-after treatment" before, and I'm pretty sure it was simply that: four BC pills taken within 24 hours, but I know it's only supposed to be effective within 72 hours after intercourse.

When I took the pills, I experienced nausea for a day (which I think is normal). Now, two weeks after intercourse--also about two weeks before I should have my period--I'm noticing some brown discharge. Could this be a sign of early pregnancy, or is it more likely because of ovulation? Is this discharge more likely since it's my first cycle without BC in a year?

Also and more importantly, if I am pregnant, would my home-remedy attempt at a morning-after pill have injured the fetus?

Thank you.