If i go out drinking until 2-3am, sleep 8 hours or so, why am i so tired the next day and depressed? is this normal?

See a doctor: If you still feel fatigue after a long rest, you need to see a doctor get a full check up because fatigue is a non- specific symptom. Many medical conduction can cause fatigue, such as liver disease, thyroid problem, diabetes, depression, etc. Depression itself can also cause fatigue.

Most likely, yes.: You have to remember that unless your body is used to staying awake until 3 am, you are most likely disrupting your circadian rhythm. Also, alcohol itself is a depressant, and could be leading to your feelings of depression on the days following your drinking. You should speak to your primary care physician as soon as possible, and possibly cut back on your drinking. Always be honest and forthcomi.

Not surprising : If you've had a few drinks (ie more than 2/day for men) and are going to sleep hours later than you usually do (i hope you don't do this every night), you get the combined effects of the alcohol which is a central nervous system depressant, and altered sleep schedule throwing off your normal pattern. Also, your body is trying to recover from the toxic effects of the alcohol making you feel tired.