According to Healthline, an adult should take between 10 and 20 minutes to fall asleep at bedtime and get about seven to eight hours of uninterrupted sleep at night. If you've been taking longer to fall asleep, or you're having difficulties staying asleep at night, or both, then you have insomnia.
Waking up several times during the night and finding it hard to go back to sleep again indicate that you have this sleep disorder. It's also common for people battling insomnia to feel tired after waking up, find it hard to concentrate and feel irritable during the day. Symptoms of insomnia can persist for weeks, months, and even years.