My partner and i got treated for chlamydia, with azithromycin 500mg last tuesday and we had unprotected sex today which is the 7th day will we be okay or? how high is chance of reinfection?

No problem: This isn't a problem and doesn't risk reinfection. However, all people with chlamydia should be retested 3 months later, to detect both reinfection and the occasional cases of treatment failure. However, I wonder if you received the correct dose of azithromycin, usually 1 gram taken all at once. If only 500 mg, ask your doctor about re-treatment or about maybe earlier re-testing.