My gf is mad at me

Hey
Well let’s get to it. Me and my woman have been together for some months now. Friends for a few years. Things aren’t perfect but no relationship is. Well couple days ago I was kind of busy at work so I didn’t text much and she was so understanding. She works from home. So I went through our texts today while I was writing this and noticed she text ed me and said that she missed me and asks how my day was going. I just noticed I skipped over the I miss you part and went into tell her how my days was. I felt bad about that. I don’t know why I just really did. She didn’t say anything about it. So fast forward to me getting off work. She just didn’t sound like herself. She sounded winded she sound just tired. The conversation lasted for a few mins. She calls me back after she leaves the gym and I’m still out and about. I told her I was go be home in 15 mins and I was go call her. Well I didn’t I ended up going to other places and stores. I didn’t tell her about it. She calls me back a hour later and I don’t answer I text her that I am getting food and I’ll call her in a sec. That didn’t go well. She fussed about me not calling when I said I was. I told her I was getting food even if it was a hour later and I’ll hit her when I get home. I told her 15mins again. I didn’t even end up texting her o was home till another hour later. She went off on me and said she will just talk to me tomorrow. I really didn’t mean it. I don’t even know why I didn’t answer the phone when I was getting food. I messed up in the past about doing sneaky stuff behind her back. She accused me of being on the phone with another chic and ignoring her. She didn’t want to talk for the rest of the night. I’m felt bad. I could have called or texted her to tell her I was going to stop at some places even if I told her I’ll be home in 15mins. My communication messed up. She is acting so distant to me. No sweet good morning paragraph. They are all dry now. Barely text throughout the day now. She not that talkative with me. We were seeing each other this Valentine’s Day weekend and she doesn’t seem excited anymore. The hotel reservation are no longer there. Now she thinks I was talking to someone else (in that way) I’m sorry if this post is confusing. I’m just writing how it is in my head. I hope y’all can help me in what to do.