I’ve been using Propecia for one week and am scared that I’m going to lose my libido…?

I heard that one side effect of taking Propecia for male pattern baldness could be impotence or loss of sexual desire and I didn’t think anything of it… I started taking the drug and within one week noticed a drop in my sex drive and a few other changes down below (in size) but ignored it. Anyway, 2 weeks later and i’m still kind of un-interested and had to force myself the other day as I was so worried. Is this all in my head? Is there anybody else out there who has taken Propecia and experienced loss of libido/impotence/lack of sexual desire? I’ve done loads of reading on the net and it seems that this is a BIG problem for lots of men, and some of them…. the side effects have been irreversable. I’d rather stop taking these now if thats the case. Any advice Much appreciated