you should check a day or so before ur periods it could negative so check a few days after your periods it could be that you are pregnant depending when you were ovulating.
Well you can take an early pregnancy test (like first response early response) 6 days before your missed period although I would recommend taking it no sooner than 4 days before your missed period (tested negative 6 days before and positive 4 days before). You symptoms may also be due to PMS. I get very tired and bloated right before my period starts. Was the yeast infection diagnosed at the doctors office? If not or the yellow discharge was not present at the time I would call them back and get some STD cultures done and also have the check for bacterial vaginosis. It may not be any of those things but better to be safe than sorry. If you had unprotected sex it is possible for you to be pregnant but again I would try to wait until 4 days before your missed period to test with an early result test. If you don't want to use an early results test then wait until your period is about 1-2 days late. Good luck.
Anytime you have unprotected sex there is a chance of pregnancy. You can start testing 14 days you had sex. Good luck to you.