How do I cope with wanting a baby but not being able to have one?

How do I deal with the fact that I want a baby, but am unable to have one? I am 23 and a college graduate, and we have been trying for at least 2 years to have a baby, with no success. (Please don't tell me I have all the time in the world, because this is not true, and certainly not helpful.) My doctors agree that there is nothing wrong with me, but I still have no answers. Every time I see a baby I get this feeling, and I know it is something I want in my life. I spent my younger years scared to death of accidental pregnancy, and now I found someone who I will share my life with and it seems that it just won't happen. How do I cope with this? I don't have a very supportive family and all my friends just tell me how lucky I am NOT to have a child. It hurts and saddens me because this is something I know I really want.