lost 3.5 lbs in one day while bulking.. is it just water?

worked out sunday at 4 pm weighed 216.6. sunday i was up till 5 am had a couple of beers but made sure to eat. monday worked out at 4pm again and im 213.1... wore same clothes same shoes same scale etc. so i said fuck this shit and yesterday i ate like f'in no other and today im f'in 212.4 same time same clothes etc. WTF!! im 6'7" 20 years old taking creatine and whey and get at least 250 g protein a day. did i just lose water weight? how much muscle can you lose in a couple of days? im so f'in mad im eating every 30 minutes now. thanks for any input.

You can lose a good deal of muscle and water within several days. You probably lost a good deal from drinking alcohol, probably water from the cells that were holding water from the creatine...

mostly water weight alcohol dehydrates you

fuck yeah.. i went back to the gym after i ate everything in my house and drank tons of water and at the end of my workout went back to 216.5!!! thats over 4 lbs gained in about 6 hours, im stoked