Pregnancy after the death of a child.

I am 26 and the mother to two beautiful children. I had my first daughter when I was 19. I was dating a guy for a few years. I thought he was the love of my life. He convinced me that I needed to get pregnant to stay with him. So I did. I love my daughter to the ends of the earth and wouldn't change it for the world. When my daughter was 2 I left her father. I met my now partner and we have been together for almost 6 years. After 1 1/2 years together I got pregnant with our son. Our son was born September 6th 2011. We lived a fairly normal life. After the birth of our son I wanted my tubes tied. My bf convinced me not to. I didn't want any more kids. I ended up getting the iud. October 29th 2013 our whole world turned up side down. Our, then 2 year old, son was diagnosed with leukemia. He fought so hard for 8 months. His cancer was just too aggressive. He passed away on July 17th, 2014. After some time we decided we wanted to try for another child. In February 2015 I had my iud removed during a surgery that was also removing cancerous cells from my cervix. My doctor said I shouldn't have any trouble getting pregnant. We have been trying since February. I religiously track my ovulation and such. Still nothing. I had no problems getting pregnant the last two times. It was so easy....I didn't track anything. .we just had sex and bam I was pregnant. I'm not sure if it's the stress related to trying to get pregnant after losing our son that is a problem. Honestly I'm not even sure how I'm going to handle having another child after our son's death. They say that if we do have another child that it's possible they will get cancer too but it's nothing that should stop us. I want this baby but I'm scared. Has anyone else had a child after the death of a child? Not to be rude but I'm not referring to miscarriage. I have had a miscarriage and it wasn't nearly as hard or emotional to get pregnant after vs watching my 2 year die. How have you dealt with it having a child after the death of another. I'm having a hard time watching all my friends get pregnant with no problem. One girl has 2 children already and she always complains about them. ..like 24/7...she just posted that she is pregnant and I almost lost it. Then the people who have like 9 kids and just keep popping them out like it's nothing and I'm over here trying my hardest and it's not working. I don't know what to do anymore. Any advice regarding any of this would be helpful.