Took three HPT and results negative. However, my last period was in May 20,2011 and I haven't had my period since. Despite missing my period I have noticed that my belly seems to be growing everyday not only that but stretchmarks along on both sides of my stomach. My boobs are very tender and swollen. My stomach tightens up when I go for a short walk around the block of where I live. Could I be pregnant?

Have you seen a doctor, done a blood test, requested an ultrasound?

That would be my next step.

Very possible