Hey I'm 17, I'm really worried cause my period is now 18 days late, but my boyfriend told me to take a test a couple of days ago and I took two, they both came out negative. I used the clearblue ones that are apparently over 99% accurate so I'm now really confused.
Over the past couple of weeks as well I felt sick everyday, I'm always really hungry, I pee a lot more than usual but I occasionally get very mild stomach cramps or twinges.
The feeling sick has stopped now but I still pee rather a lot and have a much bigger appetite.
What does this mean, does anyone know?
I really need an answer cause I'm getting freaked out.

It is not unusual for periods to be off once in awhile still at 17, so it might just be from that. Maybe you have been fighting some sort of stomach bug and that is the reason for feeling ill... especially since it seems to have cleared up now.
See what happens with your next period... if still a no show, try another test or check with your doctor.

Okay, I will do thanks.

Im wondering again.. today I was outside on a lunch break when I got this strange wrenching feeling in my stomach, then instantly I felt as if I was going to throw up.. I broke out in a cold sweat and my vision went all blurry, I felt like I was about to collapse.
But then it passed literally 5 minutes later and after that I felt absolutely fine.. my next period isn't due yet but I can't wait any longer.. I'm going to the doctors tomorrow.

:(

Good idea... they will do a urine test in the office, but may also have you get a blood test. Hope it turns out well for you.