Thru my research, I found out some causes of my lack of sleep, or waking up from 1-3 am and cannot go back to sleep.
1) Lack of electrolytes (actually, it is salted water). Drinking 1 glass of water with pinch of salt (not too much) before going to bed will do. Electrolytes will be absorbed by body first before the excess water will go to your bladder, hence it will take time before you go to bathroom in the middle of the night.
2) Stress, anxiety, etc., Keep your brain away from your problem, specially about money. Reminiscence of good things or stories of your life that happened back. Soft classical music (or any) will do. Anything that will keep your thinking away from your stress.
3) Alcohol, coffee, tea, smoke, or any stimulants before going to sleep. These are like steroids that keeps your body awake. Stimulants will kick 2 to 4 hours after you take, hence waking up in the middle of the night.
4) Room temperature. Change sleep clothes. If you feel cold or hot, go change into appropriate attire. Your body always trying to adapt to outside temperature felt by your skin.
5) Keep yourself tired in the whole day. Walking, biking, sports or work. If you are already retired (60 +), find ways to keep you tired (hobbies, sports, etc.). Sleep will make your body relaxed and return to normal.