I think you should be OK. However, just monitor your symptoms, if you feel you are not doing well, then I suggest a visit to the ER or an urgent care center if one is nearby.
You should be ok. What you need to do is just be aware (not paranoid) of how you are doing. If you got less than an actual dose of antibiotics then you should be fine. People do snort things but usually it causes the sinuses to mess up when they snort something they shouldn't. Just monitor your breathing (don't freak yourself out, like I said, you should be fine) and monitor your cordination.
If you notice anything wrong, and I mean that you know is wrong, go to urgent care unless it's a life threatening (which it shouldn't be) and if it is, get to the ER.
When you get a chance, get an appointment at the doctors.
It's hard to estimate. It wasn't very thick or anything. I just noticed the air was a bit rugged along with the bitter taste and put two and two together. I noticed a bunch of white dust on the ground so it obviously broke into dust and was in the air for a little while. I vaccumed if all up, and the room is relatively clear of it. I'm pretty sure it wasn't more than an actual dose. But I know that people like to snort pills to get it right to their brain, but I don't like the idea of getting antibiotics on my brain. heh.
Approximately how much did you inhale?