#1. Never heard of weed contributing to ED....could happen though.
#2. Depending on how old you are, that could be a huge factor.
#3. Go to the Doctor, he/she will help you.
#4. Self-fulfilling prophecy - If you are worried or even thinking your lil buddy might not perform, it won't. Trust me, it has happened to me.

So really, my prescription for love for you, is, get some meds, and relax. RELAX. Your lil buddy will do its job if you allow it to. The mind is a strong thing, allow the BODY to be stronger.