I’ve taken Propecia for one week and my hair feels way thinner than it was. I have long hair and I’m a male. Should I stop?

Okay, so I am a male, 21, and has long skater hair. I had some receding hair and the hair on top was thinner I thought than the sides and back. So we went to a dermatologist and she said I was not balding at all but put me on propecia. I want it thick. So exactly one week later, I’ve been taking it and my hair feels so much more thin everywhere. Especially in the back. I need to have thicker hair cause that was my goal. Should I stop? Also, if I do stop, will it go back to the way it was before?