3 weeks late on my period!!!!?

hi i'm 3 weeks late on my period and i have done 5 blood tests all were negative. i also have done 4 hpt's all had faint lines that you could see straight away. i'm also nauseous moody and sleepy all the time. i did another hpt today and it had a faint positive line that you could see straight away. also i have been cramping with no bleeding and i have been secreting alot of fluids down there. and i get very emotional like crying at anything all the time.could i be pregnant?