2 days late,negative result on test.any experience?

i tested today and UGHH it was negative..i didnt wana get any expensive tests so i got one for like 6 bucks...anyway i feel so sleepy for the past 3 days and today just a little nausea in the morning but thats all really not much symptoms, my knees hurt today when i stand up.also i keep running to the bathroom thinking AF is here but nuthing,i had a pad on for 2 days now and nothing, just some tiny light yellowish spotting for 2 days now...anyone had this going for them before?? i guess it was too soon to test. my cousin tested the day after she missed her period and got a BFP thats why i wanted to test..i have a normal 28 day cycle never miss a day...any answer is great thanks a lot.. P.S. not stressing or anything i just hope im pregnant =)