OP I'm in the same scenario as you
lost my aunt on the 5th and being going in and out of it just trying to distract myself with anything I can to cope. I've been dealing with a wide range of emotions, particularly the guilt for not making more of an effort to see her last time I was in town thinking I'd see her agian when I move back home. God had other plans. My mom has been hysterical and its had me worried to the point i cant sleep thinking about my aunt and how moms is handling her passing. Almost lost my mom couple months ago when she lost conciousness while driving to a doctor's appointment, so I've been on edge. My been going through complications since having both his legs amputated and, etc etc the dark cloud persist. It's to the point where when things seems to be good I'm always waiting for the other shoe to drop so to speak. I truly understand the weight you're carrying OP.
It's normal to feel guilt when this happens because we tend to obsess over how we could have done more etc.
take solace in the fact that you were with her in her last moments. some people dont get that. . My advice is to distract youself with some hobbies...literally anything you can for the moment, just to get past the initial shock.
I fought through 10 years of depression triggered by a death of a family member back in 2007, and I dont want to go back so I'm trying to deal with as productively as possible.
take it easy. cry until you absolutely cant anymore, get all of it out. and jsut distract yourself because the soul crushing weight of dealing with death of loved ones will eat at you and ways that... trust me OP
My prayers are with you, you're not alone and I hope you can get through it my G. other than that let time do the healing
be strong breh, I'm with you