Trouble sleeping so I took Nyquil?

I haven't slept well for a month, so finally I tried Nyquil. After about an hour it kicked in. I fell asleep but periodically last night (after taking it) woke up (1am, 2am, 3am)...I had only gotten about 3-4 hours/night on average but after taking Nyquil, I slept for 11 hours. Now it is nearly 4pm and I still feel exhausted. Has anyone else experienced this? I don't know if it is still having some sort of effect on me or if it allowed me to sleep but the quality of sleep wasn't good. Anyone have ideas?