Some antibiotics can interfere with the effectiveness of birth control. Assuming you're not TTC since you're on BC: if you're not pregnant this time and don't want to be, definitely check with your doctor next time you are prescribed antibiotics to let him/her know you're on BC and use a back-up method of protection. GL.
*****STUCK IN BOX********
The above is true, OP. I'm surprised your doctor didn't warn you about this. Since you have a negative pregnancy test, my best guess is that the antibiotics screwed with your BCP, you ovulated early in your cycle, and you got your period on August 4. Which is why you don't have one now. It is also not unheard of for no bleeding to occur during the placebo week, especially if your pills were impacted by the antibiotics.
Theoretically you COULD be pregnant, so if i were you i'd take a test once a week until you get a period. And i'd seriously suggest that you use back up protection while on antibiotics.
i'm overly cautious - i think during the 13 years i was on BCP, i had condomless sex 3 times. All with my current husband, who i was with for 9 of those 13 years. i like to make SURE nothing goes wrong. And now that i'm TTC, we are having all of the unprotected sex and no baby yet. Sigh.
Yes, of course you could be pregnant. You had sex so no matter what bc you are taking you def could be pregnant. I have a friend who used the pill successfully for like 6 years no issue. She also has some other things that would make getting pregnant very difficult or so she was told. She had surgery and was on antibiotics for 10 days. Now she has an infant. It happens.
I have never known anyone IRL to be nauseous before the BFP shows up. Hormone surges cause pregnancy symptoms and if you don't have enough hormones to turn a test, it is highly unlikely you are having symptoms. It could be in your head, or you could be very sick with an infection and that is why AF has not shown up and you don't feel well. Have you thought of going to the doctor, perhaps?
If you are pregnant enough for symptoms, you are pregnant enough for a positive HPT. I also agree with @delujm0 . Your antibiotics could have made your period come earlier than the placebo week. But none of us can say for sure what is going on.
Every time I see a "could I be pregnant" thread I always think could I be a millionaire?...I bought a lottery ticket but it came up as not a winner when I checked it, but I just FEEL like a millionaire. Haha.
Re: could I be pregnant?
If you are pregnant enough for symptoms, you are pregnant enough for a positive HPT. I also agree with @delujm0 . Your antibiotics could have made your period come earlier than the placebo week. But none of us can say for sure what is going on.