Feeling extremely anxious. 3 weeks pp with baby no. 2

Internally freaking out over every little thing, on the outside I’m extremely withdrawn and just going inside myself 😞 examples... I hate my body, I’m convinced that I can’t trust my fiancé, I feel like I’ve lost myself completely and that I’m just a mum/cleaner now, housework just never ends, my patience is wearing thin with my toddler who is in the tantrum stage, I’m struggling with my colicky newborn... I don’t know, I feel really lost

Multiple times a day, I’ll be sat down and all of a sudden I’ll have that overwhelming sick gut feeling, like something bad is about to happen 😞