I notice changes in sensory processing first. Reading becomes difficult and my eyes lose focus easily/take a long time to focus. I also notice a difference in my thought patterns. My thoughts start to kind of skip around. It becomes hard to concentrate on any single thing, but not in a distracted kind of way. I very much realize that this description is vague and probably doesn't make sense unless you experience similar migraines. I do also experience visual auras, but those aren't apparent until the migraine is about to become very painful.
A full blown migraine manifests as sensory processing mapping to pain. Light and sound are unbearable even in relatively moderate amounts. One of the worst migraines I had led to the pressure of my head on the pillow making every hair follicle feel like a a needle poking my scalp. You don't realize how much your brain autonomously filters out tons of sensory input to keep your focus on a very small slice of interest until the filters break down and let everything through.
Over the counter pain pills do nothing for my migraines. Sensory deprivation and sleep are the only things that can actually stop a migraine for me. I have blackout blinds, a well fitting eye mask, and foam earplugs ready to go. Early detection is very important. If I act as soon as I notice the warning signs, I can usually avoid a full blown migriane. A large glass of water + darkness and silence will usually have me back up in less than an hour. If a migraine gets to the point of pain, I will need sleep to get rid of it and will still feel rather off afterwards. Also falling asleep with a brutal migraine is no easy feat. A catch-22 so to say.
Meloxicam has been a major help in managing my back pain. It's not recommended to take it regularly since it can cause digestive ulcers like high doses of ibuprofen. But I get bad flare ups with travel and meloxicam is very effective at helping me avoid a flare up.
It might be worth asking your doctor about if they haven't had you try it before.