I have a sleep problem (wake up 4am) and I don't know what to do?

Terminal insomnia. Terminal insomnia is classically associated with depression. When was the last time your had a comprehensive medical evaluation to include assessment of sleep. I agree with the recommendations for sleep hygiene. 1. Keep a regular bedtime & wakening time (to include weekends). Get up the same time each day, regardless of what time you fell asleep. 2. Make a regular, relaxing bedtime routine. Relax.
Sleep hygiene. Avoid caffeine, alcohol, moutain dew, energy drinks. Avoid strenous exercise 4 hr before bed time. Take a warm bath. No tv, radio, computer when ready to go to bed. With your doctor go over stress, anxiety, depression, or medical conditions that may cause sleep disorders and treat the cause if any. Then consider sleeping pills.