In doubt

Let me first say that I made the decision to be a nurse when I was 15. My mother was diagnosed with kidney failure and she is on dialysis. Not many years later,I got married and had a son. He was a street runner and never supportive of me. I enrolled in college to get my prereq's out of the way. That did not go so well. I wondered all of the time about my son or what female he had at our home,etc. I was abused emotionally and physically. I never got wanting to be a nurse out of my head. After he walked out on me and our son, I thought that my life was over. Little did I know that my life was just beginning. I moved to another state and got a job working in a factory. That is where I met my current husband. Soon after I got pregnant with our daughter. It was after the birth of my daughter did I realize that I needed to go back to school. I am in doubt because I have a 11 month old, a 5 year old and a 27 year old.( ). I know that it will be hard but I don't think that I can handle challenges very well. I love taking care of people. That is my passion. How do I get rid of that doubt? How do I challenge the obstacles that I think are hard? Even though my hubby is supportive, I am still afraid.