How do you take care of yourself when you are just too sad

Im 38w. My self steem is so low, I feel worthless, useless and a terrible mother. I have a toddler to care for on my own and as much as I try I can't get over the idea I'm letting her down, I'm not doing good, I'm a horrible mother. Everything I do is wrong. I don't trust anyone. I have no friends, I have no family, excep for my mother with whom we are staying with and the person criticizing everything I do with my baby. I have bad memories from her house but I have nowhere else to go. I used to do self care, I was so confident on how I was raising my daughter, I would do my skincare every day and night, now my eyebags are terrible, I look dead, I'm tired all the time, I barely shower, the skin on my hands is cracking and bleeding, I barely eat a meal or two a day (literally no one notices if I eat or I don't) how do you even take care of yourself feeling like this. ((Toddler is fed 4x times a day, teeth brushed, nails cut, hair brushed and styled daily, clean clothes, bath every other day, diaper changed as soon as used, she is fine I would never neglect HER))