Am I being a bad friend?

My friend called me and asked me to attend Church with him at the last minute. In general, he tends to ask to hang out without any notice. I don't have a hectic life but I am in school and working full-time so sometimes the timing is off and I have to decline. Like today he called me an hour before wanting to go to Church which didn't leave much time for me to get ready. Plus I am trying to write a paper today that is due tomorrow.

Sometimes I feel he is not a good friend. I am going to be having surgery next month and need someone to pick me up from the hospital. I asked him and was told if he's in town he'll do it. It was a bit disappointing because he knows I don't have many people to count on. Whenever there is something going on with him I am there even financially. Sometimes I noticed when I text or call him he may not answer or reply or take a long time to respond. Though recently he reached out to me asking where I had been. I had stopped texting/calling him because I got tired of no response.

What are your thoughts? Am I overreacting or am I a bad friend or is he?
Am I being a bad friend?
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