Sometimes it takes up to 6 weeks to feel completely normal. You should try to find a support group to help when you start feeling like you need to take a pill. I had a similar situation with zoloft (antidepressant), while they're not really addicting, my body became accustomed to having that chemical and when I quit cold turkey, I felt like I had constant jitters, achy, irritable, and just, as you said, not fun. I started exercising more and talking to others in online chat rooms about it. And now it's been almost 8 weeks and I'm feeling better everday. Good luck!