Hello, I would be happy to help you.
Some of your symptoms might very well be related to pregnancy
. Assuming you are 12 days DPO, it sounds like you are further along without a period than normal for you.
The earliest that a test will turn positive is about 2 weeks from when you had unprotected intercourse
. So the latest that it will turn positive is going to be 2 weeks after the LAST episode of unprotected intercourse this cycle.
I hope this helps.