Am i weird for feeling this way?

So yesterday my best friend of five years told me she'd been dating this guy for like 9 months now. I obviously had my doubts cause she barely replied to my texts anymore and the very few times we did talk she'd always tell me about smth new she did with him, that yk she would've done with me before >:D.

She used to text me a lot abt random things that happened in her life and even those stopped. All of this I just chalked up to her being busy with uni or wtv. Now I'm realizing it's all cause she'd actually been dating him this whole time and I'd naturally shifted lower among her list of priorities; which definitely upsets me but I can deal with that.

What really throws me off is that she didn't tell me she'd been dating this guy when apparently all her college friends and random ass friends she isn't even that close with knew. She was apparently "bawling her eyes out" on the day she realized she liked him; and a few weeks later they started dating. Like ts hurt me even more cause wdym she didn't think to come to me even when she was upset?