I am also a caregiver for my mother and brother. Emotionally, I am in a similar situation - depressed, crying at times, not interested in things around me, feeling like I am stuck in a box and can't get out. I feel for you and wish you the best in the future. The things that help for me are using Cognitive Behavioral Therapy, speaking to a counsellor, and speaking to my family doctor. This improves my reaction, but doesn't fix the root cause, but gets me to a better place emotionally, which is good. As I said, I wish you the best, keep in mind that what you are doing is good, your mom appreciates it, and us caregivers understand and your feelings are normal.