I'm failing as a caregiver and feel SO distressed!!!

Hi Everyone. Sorry I've been MIA for a while. My mom just had another surgery for her CHF and peripheral artery disease. She's home now but is still weak and can't do much for herself. I'm still having bad panic attacks, severe depression and the chronic pain has gotten worse. I can't keep up with things like I used to and I feel SO GUILTY!!! I'm totally alone with my mom and s-father and am so overwhelmed! I stay in my room most all of the time. I'm beyond crying. I'm also in the full stages of Menopause and it's tearing me apart physically and emotionally. My mom is buying clothing and shoes out of catologs, and I can't afford toothpaste! The disability check I get each month doesn't cover the bills I have. I have to ration my meds. I can't get away from the house b/c I don't have the money to put gas in my car and the pain I have is too bad for me to drive. I don't have any friends to call and talk to and can't afford to see my therapist at this point...when I need her the most. I won't be able to see her for the entire month of May either. I can't stop the sadness and guilt I feel. I'm an only child. I wish I had a sibling! My mom continues to smoke cigarettes even though it's a slow suicide for her to continue to do so. She sits at the kitchen table most all day long, smoking. She has NO hobbies. She won't even read. My s-father sleeps most all day. I get panicky when I know I have to leave my room and go out to be with them. The guilt over me wanting to avoid seeing them like that is awful! I feel like a horrible person for wanting to just be alone. I love my mom dearly and don't want to lose her. I have no other relatives, but she's not the "mom" I used to have. Since my pain is invisible (herniated discs, fibro, osteoarthritis, myofacial pain syndrome, CRPS, etc...), I feel like others think I'm fine, since I look fine. But I'm not fine at all. I'm falling apart! I did s/w my mom's social worker in the hospital and she agreed that my mom needed nursing care to come into the house to check on her. I finally had it set up to get some help. When the nurse called to say she was coming to visit, my mom told her "she did not need any help" and refused to have the visiting nurses come in. I'm 50 years old and have absolutely no life of my own. I have a curfew here, living with my mom and s-dad. I have no privacy. Friends are long gone. No one wants to come into this house b/c it's so dysfunctional and depressing. I don't blame them. My s-dad always insults any female that comes into the house, sexually. I grew up with that kind of abuse my entire life. I won't subject anyone to what I've been through. I can't date b/c I have nowhere to bring a nice guy home to and I'm so limited in when I'm "allowed" to go out b/c of all that needs to be done at home. My puppy (3 year old Pom) keeps me sane, but I don't trust leaving him at home without me b/c I fear that he could get out and be harmed if my s-dad doesn't watch that he doesn't run out when he opens the door. I almost lost my puppy once b/c of him not being watched properly. I'm so sorry for rambling. I feel so horribly alone and hopeless and know that I'm not alone. I know that everyone here is going through many similar feelings of being overwhelmed. I was a nurse for 26 years before having to go on disability, and I was never SO stressed taking care of 10-15+ patients at one time, as I am in taking care of just two. I used to have such a positive attitude and hope. I fear that's gone forever. Thanks SO much for all of your support! Love and Strength to you all!
Kathy K.