Help please!

My period is 7 days late, i took one hpt, got a negative result. But as of the past 2 weeks, I've been quite backed up, with steady and intense cramping in both my stomach and back. I've had an increased appetite, I'm always sleepy, and it seems once i start my day i instantly get nauseous. I have a second test, and its been 3 days since i took the first one, i just want to know when i should take the second test, and what your opinions are.