What Causes A Delayed Period,pregnancy Symptoms And Negative HPT?

I never have a 28 days cycle. I had my periods on may 5th and had my next period on the 10th. This month I have all the symptom that can cause pregnancy like nausea, vomiting sensation, tiredness, breast pain, slight abdomen pain, mood swings etc.. and it s already the 15th. I took a home pregnancy test yesterday, it came negative. could there be any chances that I am pregnant?