I'm a little confused

I've suffered insomnia for 20+ years. Decided to be more natural and proactive with eating better, routines, mindfulness etc. I take magnesium/potassium for my neck, back n pms and found it aids my sleep. It got worse so went to my doctor and we decided on trying melatonin supplement as its natural and meant to be great for sleep. Two nights on it and I feel its not doing anything. Still taking a hour+ to get to sleep and I'm waking more then normal. Has anyone experienced taking this. How does it normally work/help etc. It costs a lot in nz $35 for a months worth guess I just would like to hear others experience