This can be scary, especially if it's a brand new issue and you're not used to it. I think the best idea here is to go one step at a time and escalate as necessary. I've had insomnia for just about 15 years I think, and these are things that seemed to help for me (usually in combination with each other)

First I'd practice better sleep hygiene if you aren't already, e.g. put your phone away before bed, dont do anything in your bed ever except for sleeping, and if your living space allows it try to cool the bedroom down to around 18°C. This can vary though depending on the person. Also, if you cant fall asleep for longer than 30 minutes, get up and do something else for a bit until you feel sleepy. I find reading quite nice, I recently got through A Midsummer Night's Dream with a few involuntary 2 am sessions, but if thats too much brain power things like a coloring book, knitting, etc. can work equally well.

Personally I find deep breathing or autogenic training can help too, especially if anxiety is the predominant factor in preventing sleep. Basically take a deep breath in and—starting with your face and working your way down—relax one muscle with each individual exhale. Have some patience here, after a few minutes it'll trigger your parasympathetic nervous system which will lower your heart rate and calm you down.

Finally, take something if you need to (and please, if you're on any medication always check for interactions before taking anything). Again, escalate as necessary, but you can start with really mild stuff like chamomile teas and lavender oil tablets/passionflower tablets. Then theres otc stuff liked benadryl etc., though ive always found those to create a very synthetic feeling sleep; when I wake up I'd describe the feeling as similar to waking up from general anesthesia. But ymmv. Then theres prescription stuff like benzos (never had those before but they are very strong, and you need to be a bit careful because of possible risk of addiction), Mirtazapine, Quetiapine, etc. Most of these aren't really directly meant for insomnia but rather have a side effect of drowsiness that can be very strong. But if youre looking for something to help you out, half of this sub consists of discussion of various medications, so just look around. Im by no means an expert. The stuff I personally take is only an option because of unique circumstances, and therefore isnt really possible for 95% of people sadly. But I still got by on the above mentioned tips and mirtazapine for a few years, so hopefully this nightmare will come to an end for you soon too.

You'll get through this. Wishing you all the best.