Becoming a single mum

Me and my boyfriend of 3 years and my 2week old babys dad have been broken up for about a week now. Ive been really struggling since the birth of our daughter. I feel constantly anxious that something bad will happen to her, i can barely eat or sleep and just feel constantly down and alone. I feel so guilty for feeling like this because i love my little girl so much but i just feel useless and as if she would be better off without me. My boyfriend was struggling with my constant sad or angry moods since having our baby and has broken it off and has no intentions of trying to work things out again. I dont know what to do 😔