Mastitis - OUCH!! Been there, done that, not fun

I personally don't know about relationship between antibiotics and milk supply. I know when I took the antibiotics I didn't notice any problems.
What are the indicators that your supply is down? Do you fell less full or is your lo crying making you think your supply has diminished? I am only asking because I think I read somewhere that antibiotics make your milk taste a little different. However I don't know where I read that

While you had mastitis did you continue to nurse from the affected breast as often as usual? That could affect milk supply if that breast had a "break" while it was sore and painful.
If your period is coming that too causes milk to take on a different taste and can affect milk supply. You may have to feed more often for a few days to increase your supply.
HTH, let us know what happens!