PM 500mg?

Hey all

I was hoping someone could answer me these few Q. I ordered my first bottle of PM and I was wondering how much should I take starting out? they are 500 mg, and I am thinking that might be a bit much, seeing as I have been reading people getting side effects and results/breast pain with just 100mg?

also, I have been reading something about taking it for 15 days, and then stopping or something? can someone explain that to me? should I start after my period?

& i'm kind of looking for long lasting results, I read some things about the girls shrinking back down to their original size if you stop taking PM.. i'm thinking about just getting NBE and calling it a day

Thanks for all of your help & advice, loves