Could I be pregnant?

Sierra • Wife | fur mama | mommy to Eliana due 1/24/20 💗
My fiancé and I had unprotected sex during my fertile days. I'm now 10 days late and I took a test Sunday night (I think my urine was very watered down) and it was negative. I took another test Monday morning, it was also initially negative, but I looked at it a few hours later and I was clearly positive. I took a cheap .88 cent test last night which was negative and a first response this morning which was also negative. I feel pregnant (eating more than usual, having to pee frequently, very moody and emotional, very bloated, back pain, and nausea). I'm pretty confused. I can't figure out any other reason I could be so late. Have any of you ever experienced something similar and then ended up being pregnant? I'd love to hear your responses.