Ive had tons of brutal hangovers - and fear them like death!
The cause is invariably drinking more than intended. Sometimes all of the alcohol doesnt hit you till you are asleep. This seems to have been the case in your situation since you woke up with "the spins" (likely still very drunk!)
Prevention - if you know you have overdone it- a couple tylenol before bed. An at least 2 glasses of water - but if you have relly overdone it, this wont prevent the onslaught.
So the next am, asap- get some painkiller jnto you, to take out the migraine like headache. Then some fluids - best would be pedialylte, but who has a stock of that around th house. (gatorade is ok, but too acid/ sweet for te wiked nausea and heartburn that often accompanies ). So i find some salty soup. The best is some homemade chicken stock, with a teaspoon oF soy sauce or so (plus some ginger for nausea if you have any) jut drink it out of a coffee cup, slowly. At least one cup, if you keep it dow. For an hour, then try another. Then if you are slightly better, but still rough- take a gravol and go back to sleep and sleep it off.
Word of warnjng- hangovers for some reason make me horny. Avoid sex or self pleasure, the splitting head exploding headache that will result it not worth it!!!
Hangovers suck.