Why do i feel so undeserving of a good life?

Im 22.. Im a good person, never cheated, hate lying. I think im a really genuine person, i think im beautiful, but have some i securities. I have bad anxiety, and just whenever i start to feel okay, it comes back full force. I feel like i will never be able to live the life i want. Im struggling to pay all my bills, while caring for my almost 2 year old. Ive already broken up with his father after he cheated. I just feel like im meant to live a low life. I know im smart, and more capable than a lot of people. I feel so skinny, tho i workout and try to eat more. I want to feel sexy and be vibrant. But as time goes on i feel more secluded and introverted. i dont know how to do, be, or look better