Sad with my life, I'm just wanting to vent

Okay so I am just wanting to vent, to really express how I feel instead of saying "im fine". I dont know what's been wrong with me lately but I've just been feeling so hopeless and sad. I have 3 beautiful children and a good husband so I dont know why I feel like this. I feel like im a horrible mother and my kids deserve better and I think my husband is better than me and that he deserves better. I feel like if I wasn't here they would all just be happier. my husband has been working a lot lately and when he comes home I just feel like hes avoiding me. everytime I try to start a conversation with him he just ignores me or starts talking about something completely different. I asked him this morning why he was doing it and he said it's just because hes tired and hes been working alot and it has nothing to do with me. I'm a stay at home mom, I dont really have any friends, so when he ignores me it hurts. I also cant stop thinking about every single mistake I've ever done in life! I feel so anxious it makes me sick! I just dont want to feel like this anymore!