So you want to know whether you are impotent or not? Purchase a Fleshlight, surf pornography and thenceforth get aroused. Try to stick your slinky inside of it and if you can you are worrying over nothing. I haven't purchased one myself however this site sells it which I have purchased other stuff for the past year:
http://www.lovehoney.co.uk/product.cfm?p=891
http://www.lovehoney.co.uk/product.cfm?p=891