Could i be pregnant? i'd only be 2 1/2 weeks though?

i would only be 16 days pregnant. i took a blood test at 13 days and it came out neg. my last start day was around august 8th and i slept with my boyfriend the 14th..but i got a lot of symptoms. my "symptoms" may just be coming from worrying too much about it. Like for instance when i bend over or reach/twist to get something off a shelf my stomach kinda hurts. and when i sit at a desk at school for too long my stomach just starts feeling weird. my ovaries hurt me for like 5 days and stopped and now it comes and goes. i get more frequent headaches but its only like 2 times a week..i pee a lot more but i also having been drinkin a lot so it could be from that.i havent noticed any cravings yet or changes in appetite other then for a week i didnt wanna eat anything and now i wanna eat a LOT..every symptom i got has another reason as to why it could be happening..Before i took the blood test my doctor told me it may not be accurate but they'd test anyway cus the sooner i get prenatal care the better. shes sending me to an obgyn but i got a week or so before that appointment. I got another 6 or 7 days before i would be scheduled to start my period but i've never missed one so that'll give me my answer..its driving me crazy not knowing!! how accurate are the clearblues at really detecting pregnancy 5 days before ur first missed period?