could I be pregnant?

Cassidy
I've tracked my cycle for 3 years it's 21 days apart and I bleed for 4 days.. my period is 11 days late and I'm very regular.. my boobs are sore, I have constipation, highly emotional and I've had very lucid dreams! I had a blood test done 2 days ago it was negative and I've had HPT negative as well.. but I'm still late with symptoms could the HCG just be taking a long time to build up? any hope?