Slow release Melatonin. Any experience anyone?

Hi…does anyone have experience of taking Melatonin please? I just started my 2mg slow release Melatonin prescription last night to help with insomnia, and although it helped me to sleep through the night, I feel so tired today it’s as if I had no sleep. Does this improve over time? I plan to take just half a tablet 1mg tonight to see if that works better for me. Many thanks for any feedback.

Just to add to my last post…you can’t take half a tablet as it interferes with the slow release aspect of it. I’ve taken it for 8 nights and have been able to sleep reasonably well. I wonder though if anyone has taken it for a longer term period please. Thank you for all replies.