Ugh, had too much to drink last night....?

Sooo, my friends and i had a little much to drink... And when i woke up this morning, i was completely fine, but now when i'm laying in bed, i feel like I have the worst hangover ever! Ive been drinking plenty of water all day, but i think it caught up to me... Its been more than 24 hours, so why am i just feeling symptoms of a hangover?