So glad your mare is okay and that this was a false alarm. Hope you enjoy your foal. I am off to look at cute foal photos.
I wanted to comment on some of the other issues raised in this thread.
Diagnosing, treating or prescibing over the internet and without a veterinarian's license is ALWAYS a bad idea. Suggesting or prescibing antibiotics is particularly problematic for two reasons: 1.) if you get the dosage or the course of treatment wrong and undermedicate, you set the horse up for a secondary infection, which will be dangerous and costly to treat. Most self prescribed or administered antibiotics are not given long enough or for the full course to eliminate that chance. Penicillin usually needs to be given 2x/day for *10 days* 2.) Antiobiotics have a specific range of bacteria that they are effective against. Sometimes you can make an educated guess and prescribe a broad spectrum antibiotic like Penicillin or SMZ-TMP, other times it's critical that you culture the infectioin to determine the correct antibiotic. If you chose the wrong antibiotic for the type of infection, not only will it not treat the infection, it will make it impossible for you to culture and determine the correct treatment afterwards.
Second, there is nothing wrong with posting questions on an internet message board to get opinions. We've all done it, that's why we're here, right? It is important to remember that what we get from a message board is *opinion* not fact. Using a internet message board as a tool for discussion or clarification after one has a base of knowledge and can evaluate the advice given is great. Using an internet message board as a primary source, when you have no knowledge base and can't tell the informed opinion from the uninformed opinion, good information from bad, is very bad practice indeed and can only lead to frustration.
Off to look at baby photos!