IM Anxiety Attack

[Satu]

I have been stricken by an internet marketing anxiety attack. I have had an affiliate blog idea for some time (I have a domain name and installing a wordpress is not a problem etc) but I cannot get started.

This would be my first serious attempt at IM and I suddenly feel very anxious! What if my site idea is stupid and no-one is ever going to buy anything from me? What if I spend the next 6 months building a site and see no profit?

My site idea is "at crossroads" of several popular niches (fitness & health), so it could have potential for profit.

I keep thinking that I should try something more limited first, or at least build some "market research" lenses on Squidoo to test if anyone is interested in my approach to the niche.

How long do you have to work before you decide building a specific site was a mistake?

I have been hovering for some time....