Irregular Period- do I have an STD?

Hey ladies, I'm concerned here, let me tell you: 
Been off the birth control pill since July 2015, had been having my 6-7 day period on a 36 days cycle. 
In December my cycle was 28 days, then 21, now 18! 
Wtf is going on? 
I did have unprotected sex around oct, did
Notice a little Years the following day and cleared up. Then I had sex with protection and then without (same week ) and my pussy smelled bad. So I did the moniatat and yogurt treatment and it cleared up. 
So, Do I have an STD?????? Or was my infection just for being slutty and irresponsible? 
In any case, I have a doc app on feb 6, but I just need some insight. 
:,(