As far as your doc goes, call him and when he or his nurse calls you back explain that you are between insurance right now and you really can't afford the extra office visit right now. I would bet they will be sympathetic if you explain it that way. He will probably let you call in and see if you are doing better at the end of the course of antibiotics and if not then he could write you a new script this one time instead of having you come in. When he ask if you want it called in somewhere just say no thanks and ask tell him you want a written script because you want to check around for the best price. You don't need to tell him you are filling it in Mexico.