Hi Marvin, sorry to hear you are having such a tough time.
I have sleep apnea and use a CPAP. I also had a number of other reasons for insomnia. I suspect you have figured out that worries about Covid, doom scrolling and late-night screen time perpetuate insomnia. So I will just address the CPAP and your work schedule.
Sleep coaches work with sleep medicine physicians and specialize in using CPAPs. Medical equipment supply stores also have people who are familiar with the various models of machines, hoses, filters, etc. It may take some digging, but I am confident you will find someone knowledgeable. Performance Home Medical, located at least in Washington State, is a good source and may be able to refer you to someone or some company in your area.
I also used to work nights, which I assume you have to do at least some of the time as a security officer. There is no getting around the circadian rhythm issue, i.e. that we all kind of fade around 4:00 am. But if that’s your shift, the way to make the best of it is still set up a regular sleep schedule. I asked other night workers and found the following worked best for me: get off work 8:30 a.m.; stay up, doing whatever until noon (the way day shift workers don’t go to bed right after work, either); sleep about noon–6:00 p.m., go to work later that evening.
Not saying this is an absolute blueprint, it just worked fairly well for me.
Final point is about sleep anxiety, freaking out when you can’t sleep. Man, I have been there. There are a few things where trying harder does not help, including getting to sleep.
I typically wake up a couple of times during the night. I have thoughts that I won’t be able to get back to sleep. I let the thoughts just drift on by, telling myself that I would rather get back to sleep, but you know what, I have had thousands of nights where I could not, and I made it through the next day, as in 100% of the time. (I am not saying you will have many years of insomnia; I had huge, long term emotional problems to work through.)
Take care, Marvin. I really believe you will get through this.