can you still have chlamydia after being tested and it coming back negative? ?

7 months ago i was treated for chlamydia, after i was treated i got tested for everything again and it came back negative. i recently got into a relationship and it hurt so much. i ended up with thrush, i got treated for thrush 3 times as it wasnt going away and my boyfriend ended up sore too so i advised him to take a tablet incase he had it. we had sex again after 4 days and now he says his hurts again... could it be chlamydia? 

and yes before you say go to a doctor i am going to, the next available appointment is next week and im just kind of freaking out so any advice would be appreciated if you have had similar situations or if you know more about chlamydia etc.