Is this a red flag?

My birthday was yesterday, but I did not get a phone or text from my bf! I waited all day just to hear from him & it didn’t happen. I talked to him the night before and everything was fine, so I kind of worried. But, when I woke up today I saw he was on Instagram, which really pissed me off!! I waited until I heard from him, he called me & I didn’t answer. I sent a text saying basically don’t talk to me at all. After that he called me like 5 times & kept texting me.

In the text he said that he did call me twice, but I didn’t answer 🙄 & that he’s sorry & for me to answer. I’m so hurt, we were just starting to get a little more serious, so I’m really surprised. This has never happened before, even when we were just friends & I’ve known him over 10 years. Idk what to do, or even how to approach the situation. Can you guys give me any advice on how I should handle this?

Thank you all for your answers!!