I would be willing to bet that if you went to a doctor and had them run a complete blood test you would find your testosterone levels to be low. You can set up an appointment and complain of low sex drive, no ambition, motivation down and unable to maintain an errection which are all signs of low test levels. If your doctor listens to you and runs a blood test finding that you indeed do have low levels chances are they would put you on some type of HRT (hormone replacement therapy)
Dont let this scare you its common for men above 30 to have their test levels start to drop most consider the signs due to age but in fact it can be cured or resolved. I started to cycle about 3 years ago and although I am not big at 6'4 and 225 I am a good size.
http://www.discountsupplements.com/
If you want supplements this is the place to go as its far cheaper then GNC or those other places. Honestly you should try and obtain most of your diet through whole foods such as chicken, fish, meat, veggies, brown rice, ect..ect.. as someone above mentioned.
You do not post your stats but if you would like help with a diet I would be more then happy to work something up for you. If you want to research the topic the link listed below is full of amazingly helpful people and information.
http://forums.steroid.com/forumdispl...DIET-QUESTIONS
Dont be thrown off about the name the forum is one of the largest on the web and for sure one of the most informative. If you would like some farther advice please feel free to let me know as I said I would be more then happy to help you out.
FYI if you have a doc that will write you a script some test and deca will do you wonders! Sadly I dont have a doc that will do that so I source it out other ways.