Will it do my body harm if I take Melatonin everyday before going to bed ?

Can it harm my body if I take Melatonin everyday before going to bed ? Are there side effects ? I have really bad insomnia since elementary school, and nothing seems to help. I’ve tried sleeping pills, meditation, sex before sleep, masturbation before bed, warm bath before bed, and nothing seems to work. I was also on ambien, but it stopped working after a few days because I still couldn’t sleep. I tried Melatonin once before and it worked really well and fast, the only side effect was having intense dreams. Does anyone know if I take it every night, if there are any risks ? Besides intense dreaming ?