please help! Need advice

I am 16 and recently had unprotected sex around time of my fertile Window ( yes it was an in the moment thing yes ik I should've use protection) my period was due the 26th and my last period was July 22nd was the first day . I been experiencing nausea and vomit once during these couple weeks . Also exhausted and back pain. I did check my cm and it's thick white consistency and it has stayed that way since last week. I took a Walmart 88 cent pregnancy test and was negative. Need advice. Is it a hormonal thing or should I wait another week and test again before going to the doctor ? ( I do have some issues in hormonal imbalance but. My period usually always comes around the same time frame 10-25th usually every month so far) please help !