PLEASE HELP !!Need advice

So August 31 and early September 1 . (High fertility days) My Bf and i had sex (Obvi). Like maybe on the 8-9th if September he later tells me he ejaculated inside of me and I should consider a pregnancy test within a week or two. My cycle cane two days late. {I have had some stressful days before my cycle was do but still struck some concern} period (Was scheduled for the 12 came on the 14) Lasted for 3 days. Ever since then I thought i was in the clear of pregnancy because my cycle came.

(Fast forward after period) I have been feeling very tired and just different. Now Two weeks ago i have been feeling HORRIBLE! On and off lower back pain, slight dizziness and then just recently i started to get little headaches and stomach cramps and just feeling like my period was about to come at any second.

So I look at my glow chart to see that im not due for my next cycle until 2weeks from then (now is next week) . Since then i still get stomach cramps , little headaches and still feel as if my cycle will start any minute.

Does this mean I could still be possibly pregnant or like body changes ? PLEASE HELP