Is it normal if it happens?

Its been a few months since this happened. I was watching this drama and it was its last episode and I was feeling very sad that it was gonna end(this happens with me a lot, I don't like endings). I completed the last episode and it was normal but after a while I started feeling nervous and anxious for no particular reason and it felt like all of the air was being sucked out of my chest and I kept getting glimpses of the drama, idk why. I decided to take a nap and hoped that the feeling would go away when I wake up but it was the exact opposite of what I thought. I felt more trapped and I just went into the bathroom and cried and I still don't understand why I did that. I went for my regular classes after that and I felt normal around people but as soon as I was alone that feeling crept back in and it became hard for me to breathe. I kept reminding myself that I'm fine and its normal but it didn't help. The next day was the same, I cried in the shower for a long time and there wasn't any reason to cry. This happened to me only once for two days and nothing like that since then but I don't know how or why it happened. Have you experienced something like this before or is it just me?