Nightmares that feel like seizures or vice versa

Sometimes immediately after falling asleep I have super intense nightmares that I wake up from right away, sometimes shouting things, kicking my legs, or beating my pillow/bed with my fists, my heartbeat is crazy fast, and it takes me a few seconds to be fully awake and realize what's going on. I usually can't stop the movements or shouting until I'm fully awake, so I feel like I'm frozen, kind of like how it feels when going into a seizure. My boyfriend told me that the way these nightmares start is exactly how my seizures start; I've always considered them to be nightmares or night terrors, but since they're so similar to seizures I'm starting to wonder if maybe that's what they are, mini-ones if anything. And it's not just something that happens at night; if I'm napping or if I fall asleep on the bus sometimes they happen - I'm sure you can imagine how embarrassing it is to wake up on public transit shouting something incoherently and then realize that every single person in the vehicle is staring at you. I'm wondering if anyone else experiences anything similar; if anyone has any advice or even just a description of something similar that happens to them I would really appreciate it.