I can't stop feeling that I was an inadequate caregiver to my mom.

Know too that you're not alone. When a parent dies, each of us is prone to feel that the care we gave, the love we shared . . . even the person we became, was somehow inadequate to what we believed our parent expected or deserved. This will pass with time. Letting go isn't easy, particularly when so much of who you saw yourself to be was tied into the care you gave your loved one. Try not to be so hard on yourself. Instead, know how grateful your mother was for the care and attention you gave her. I'm willing to bet that she never saw it as being inadequate. Take that and turn it into a gift from her to you, now, of accepting yourself as someone who's far more than merely adequate.