8 yr old diagnosed with seizures. Scared to give him meds.

Hi. My son is 8 and has autism. Last year his doctor referred us to a pediatric neurologist at Akron Children's Hospital. It's the best hospital in our area. They asked me if my son had staring spells or got headaches. I said yes, so they gave him a sleep deprived eeg. I was sure it would come back negative. I always thought his staring spells or when he would zone out and act strange, that it was just one of his quirks from having autism. They told me he has seizures and prescribed him medicine. It was a lot for me to take in, mostly because I felt awful for not knowing he had them. He barely has had them during the day and I have been scared to give him the medicine bc of the side effects. I worry though that his seizures could get worse if I don't give him the medicine. Has anyone else had these same fears about seizure medicine? I have no one else to talk to about this. My friends don't understand. Sorry this was such a long post.