Need some comments on what to do and etc.?

Todayy, I was suposed to go to the gym with my girlfriend. The plan was to go for. Me to go att 7 in the morning and she would go at around 9. But last night I only slept for 2 hours, which means I went to bed att around 5 or 6. When I woke up, I decided not to go because I didn't look well and I knew I was going to feel well either. And so, I text my girlfriend saying I was not going to go and I explained why I was going to go and I looked really horrible and tired. And of course I said good morning and that I loved her. Unfortunity the text that said that I wasn't going to go didn't go through.whhen she woke up she called me but I was fast asleep. When she got to the gym, she went looking for me for about 30 minutes.she couldn't find me and decided to call me. She asked me where was I. And I said at home. She said wow I was at the gym for 30 minutes looking for you why didn't you text me and I told her that I did and I tried to. And we had a 10 minute conversation about why I ddidnt text her and how I tried to text her. After the phone call, she texts me saying that she was really disappointed and wished that I cared more. My reaction was WTF what am I suposeed to do, I'm already sorry. And now it feels like she is putting me down because I "made" her go and now she is mad at me. I don't know what to do anymore. Somethi g like this happened before but this time she isn't on her period. Please leave some comments on what I should do and what you think about this situation.