Waking up in the middle of the night is called sleep maintenence insomnia. It’s a very common problem that can be brought on by emotional issues like stress or depression. Physical factors can cause it too – like acid reflux, pain due to arthritis, restless leg syndrome, sleep apnea or hot flashes. And, of course, disturbing dreams can wake you too.
Most people wake up one or two times a night, so it’s fairly normal. If you don’t fall asleep within 15-20 minutes experts recommend getting out of bed, read with low light, or do something quiet that can relax you. Do not turn on the lights or the TV; both of these can stimulate you and keep you awake.