anyone out there with a special needs child?

I have a seven year old sweet little boy who has been diagnosed with Morquio syndrome and there isn't a cure for it. We recently moved and started a new job and my employer isn't happy that I have to attend so many doctors appointments not to mention I have to be at the hospital with him once a week for more than half a day for him to receive infusions. 
Im having a break down and don't know what to do. I am a single mom of two kids and I'm not playing the single mom card but I am the only source of income for my children but my children comes first. Part of me feels angry because he keeps saying oh you're taking days off when in reality I'm at the hospital holding my child while he cries and pushes because he doesn't want to have a needle in his body. It's not days off.. he didn't choose this. Any advice?