Going to sleep at night is the hardest.

I just went through the same with my Mom just a few days ago. It’s traumatic. You feel rattled. You don’t feel the same. It’s so very sad but at least we were there for them. At least they died with family near which some souls pass with no one around. Even though it was tough it was the least I could do for her. God bless you. I think our trauma will lessen with time.

Im grieving too, my mom died 5/1/22, im having a hard time

I read this and I can say I hear you...I hear you and know this is the hardest thing you have ever done in your life. I was helped by a program that helped me understand the 5 stages of the grief process.
Google that and see where is leads you. There are people in your community that are right there with you...feeling those same feelings...try to find them. It does help to talk it out with someone who has been in your shoes.
Possibly see a dr. for some help in falling asleep. There is no shame in asking for help. This is a really really really hard thing....your doctor will help you..you just have to reach out..
You did the best you could...allow yourself that ...knowing that if you could do it all over again..you would not change a thing about your care giving or your support in the end. You have to forgive your heart...then your head will follow.

The problem with caregiving is that seems to be what you remember after they are gone. My Mom aged 10 yrs in front of me. She became so frail. She would look at me and at times she was not there.

What got me out of that slump was my friends (who hung around my house as teens) telling their stories about the person Mom was. I have a FB friend who grew up with my brother who just told a story about my Mom. Thats the Mom I want to remember. When you start remembering back when, those last few months start to slip away.

I had similar problems after my dad died. I never thought I'd get his face after he died out of my mind, then one day about a month later, I couldn't conjure it up.
Fortunately, I didn't have that after my mom died even though I was with her after she died while I waited for the mortician to come.

Now all I have are the happy memories, and I think of both my parents every morning when I first wake up.

Ask your doctor for an Ambien prescription. That's what helped me sleep after suffering PTSD and staying up all night crying. Ambien knocked me out and kept me asleep all night. I took it for a whole year with no issues getting off of it cold turkey. Total life saver. Sometimes we need help like this for a while till our mind calms down.

I believe in feeding the subconscious mind a positive thought every night when I first lie in bed.

The subconscious is the ruler, it keeps you breathing, it keeps your heart beating and your conscious mind only believes what it is fed by the subconscious.

Repeat the thought that needs to be addressed and after a time the negative mindset will go away, this issue will not be repeated.

Then move onto another negative thought that you need to resolve.

There are many books published about the subconscious mind, might be a read for you!

Sending support your way!

I can also relate. The first few weeks after my mom passed I'd, and I know this is going to sound stupid, but I'd feel like I could sense all the ghosts of my mom's siblings around me. The last week of her life I was practically living by her bedside and I had this kind of droning sound in my ears. It almost sounded like a distant choir singing. So at home after her death I could still hear it and I'd walk around my place feeling like I was losing my mind. Grief does funny things to a person.

One night I even went for a walk in the middle of the night. (Not recommending this) But it did help. It distracted me from my thoughts.

So, I think you need to do just that. Distract yourself. Much like CWillie said. Find something to occupy your mind. Even if it gives you a small break from all the regretful and guilty thoughts. Eventually, if you do this enough you'll find you won't even have to make a conscious decision to do it. It will happen naturally.

I know what you are going through and it's hard but it will get easier. Have faith.

I can relate, my mom and my many regrets were on my mind almost every night for many months.
I believe it is helpful to mindfully stop yourself when you begin the loop yet again and redirect your thoughts to something else, whether it is a happier memory or something else altogether like imagining yourself in your happy place. If you can't manage that then read a book, watch a video, or get up if you need to, just don't wallow in it - the more you allow yourself to replay those memories the stronger they will become.