Has Anyone Took Phentermine ?

Okay so I just started taking Phentermine doesage 37.5 last Wednesday, my af was supposed to come June 8th and of course today is the 12th , which means i'm 4 days late. I don't believe I am pregnant , but do think that i'm late due to the pill . I just wanted to see if anyone had a messed up menstrual due to this pill ???
I have no pg symptoms . I do have a sharp pain on the right side of my lower abdominal and a lil bit of nausea.