I have been taking amoxicilin 500 mg for two days and i missed one dose, should i wait until the time of next dose and should i take two tablets next time?

The idea isa to maintain a constant titer of antibiotic. If you miss a dose the titer drops, encouraging infection rebound and/or antibiotic resistance. Take a tablet immediately and then reschedule the rest at the interval prescribed by your practitioner. If you are on an 8 hour interval (3/day) take your next pill 8 hours after the one you take now, then 8 hours after that, etc.

All of this advice applies to many medications, including amoxicillin: if a person remembers a dose soon after missing it, she should take the missed dose immediately. However, if a person remembers a missed dose closer to the time to take the next dose, the best approach is to skip the missed dose and not to take two doses at once.