I've had meltdowns from changes in plans. I had a big one somewhat recently. It kind of confused me because it was a change that most people would be happy about if it happened. My youth group was going to a soccer game then a concert afterwards and I didn't get tickets to go and didn't really want to anyways. I had gone before, but I'm not good with going out places. My mom apologized for not buying me a ticket and I said I was fine. I had my friday planned out for myself. I was taking a nap (part of my plan) and my mom called back excited and said they had extra tickets for me to go and my mom told them I would go. I got really upset. I threw my phone a couple times, slammed some doors (which I never do), threw my stuff off my desk, punched my wall a couple times (made of cement, my room is the basement) threw other stuff around, and started crying. To add on, I couldn't find what I needed to take with me and also didn't want to upset my mom because she wanted me to be happy. I got to the church, and I had to hold in tears, but my mom called the youth pastor and told him "I didn't feel good" and she picked me up.
Usually when I get meltdowns though, it's just me first trying to not cry, but then start yelling and end up crying then going to my room to be alone for a while in till I'm back to normal. Sometimes I fall asleep then wake up and be ok, and sometimes it might go into the next day. If it takes to the next day, then I don't talk to anyone in till I'm better.
That's how my meltdowns are. So, how over you would describe those, then there you go.