RARE late, light period pregnacy symptoms, negative results

me and my boyfriend of 6 years recently started a sexual realtionship. in the month of april, we had sex without a condom, neumerous times (on the same day) on the dates of the 18th, 20th and 23rd of april. He ejaculated in me most of the time. My last period was april 4-7. I have been experiencing pregnacy symptoms like nausea, fatigue, gas, mild constipation, urinating alott more frequently, iritability, certain fsmells making me sick, the smell of food making me sick, back pains, feeling tired- sluggish, breast tenderness, uncomfortable in my stomach area when sitting down or in a vehicle-especially on the bus, hunger, and camps on and off. However, I have taken three hpt's and they all came back negative. My period has never been late before, but yesterday, the 8th, i started my period. Atleast i think it's my period. It is 6 days late. Usually, my period starts off heavy and then lightens up. Yesterday, it started off rather light- almost spotting, with alot of clear discharge. Right now it is not heavy, but the flow is very thin with the same clear discharge in it. I feel very nausiated and tired. My back and breasts are quite sore. My mother had her period, well she bled, her first few months with me. She thinks that I am pregnant, but i want a few more opinions. Let me know what you think. ? !
Ps. I'm not worried. Me being pregnant is not a bad thing, so please don't feel sorry for me lol. however, i would like answers as soon as possible. Thanks. 8)