Please help?

I think I'm about 6 or 7 dpo, had unprotected sex on the 12th, AF due on the 30th, my bbt has suddenly skyrocketed to 98.6 two days in a row when usually it's low 98 or high 97 after ovulation.
At what point does implantation occur? When can I expect pregnancy symptoms if I am pregnant? Obviously, y'all aren't pregnancy tests, so you can't tell me for sure, but do you think I could be pregnant?
I'm not TTC and I'm starting to really freak myself out. :(