Help??/TW?

Just got my cycle after a few months of not having it. I feel like absolute dog crap. It's heavy and I feel very foggy and exhausted. How heavy is too heavy? I soaked through an always maxi pad size 5 I believe in maybe 3-4 hours (idk I was at an event so couldn't change it until after. It completely stained my underwear 😭)

Should I be concerned? I'm drinking a Powerade zero sugar to try and stay hydrated