Took 1g of azithromycin at 6:30 am the 28/06.my partner took 1g 25/06. we had protected sex today (5/07) at 5:30 pm.should we worry about re-infection

No but: As long as you keep having a protected sex the chance of reinfection is small

Azithromycin: Protected sex is very effective, but azithromycin doesn't protect against herpes,yeast infection or hiv. I think it could protect against gonorrhea, chlamydia and syphilis, but I couldn't guarantee this. I would like to know what A specialist in infectious disease thinks about this,although many don't recommend taking antibiotics prophylacticly. Protected sex is best.