I am 35 yrs old and extremely frustrated and ashamed. I have problems in bed and I don't know why. I don't feel like I should be old enough to suffer from ED but I can't keep an erection to save my life... Tired of making excuses. IS THIS NORMAL??

You would have to check with a dr to find out what the problem is. Then there are different things for what ever it is. You could have stress, a low libido, or some other problem.

Does low T levels cause this too?

I'll reply later tonighr. I can't do much from my cell phone

Hope this is helpful
Is It Low T? 9 Warning Signs of Low Testosterone (http://www.healthline.com/health-slideshow/low-t#8)