Trouble conceiving...

I don’t know where to start. I haven’t actually been trying but I’m definitely not doing anything to prevent it. I want children of my own. I want to be happy for all of my friends and family but a part of me just wants to crawl in a hole and cry every time I hear that someone else is pregnant. I question my worth and wonder why I haven’t been so lucky. I thought my spouse and I finally begun wanting the same things. At first, he said he wanted children. Just not until our careers, my education, and the house renovations were complete. A couple of weeks ago, I was playing with our nephew and instinctively turned to him to say how badly I wanted a son of our own. He agreed that he wanted a son and that although he would never be quite ready, he wanted to start trying now. This morning, I informed him that my cycle had started and he was very enthusiastic. He says that he was just thankful that it was present because a few months ago I was having problems with my cycle. I went three months without a period and I was prescribed medroxyprogesterone. I feel that he has changed his mind about wanting a child right now and may just be trying not to hurt my feelings. My doctor won’t do anything to help us conceive until August. He wanted to give it a year to occur naturally before he gave me any treatment options. I am 30 years old. I don’t want to wait until it is too late. It has taken everything to keep from falling apart every time someone says “You will be such a great mother,” or “You’re so good with the kids! When are you having your own children?” I’ve become distant to some of my closest friends. I give them all that I can think of to buy to compensate for the time I never seem to have. Why am I like this? What can I do to increase my chances of pregnancy? Please help.