DOLLAR TREE TEST?!!

My period is irregular but my average cycle day is 32 days, im on day 38 and still no period. I ovulated and had sex around day 20. Ive been feeling extremely nauseous more than i ever felt nauseous before, my nipples are larger and hurts to touch, slight weird cramps, gas, metalic taste in my mouth, extreme hunger, feeling Hot, ect. I took two dollar tree test before my period was due and got a negative and i took another dollar tree test late last night on cycle day 36 and still negative. I dont know if something else is going on with me like if im getting like a bug or something or what. i think dollar tree test are pretty trust worthy but i dont know if i just wait another week and retest with first response or just expect the fact im not pregnant and my period is about to start or something else is wrong!