No appetite PPA

I’m 12 days PP and dealt with bad anxiety since giving birth and ended up losing my appetite 3 days ago. I got prescribed a low dose of lexapro and I’m wondering when my appetite will come back. Everything is making me feel nauseous and I’ve even vomited a couple of times while trying to force myself to eat. I feel so weak and tired all the time and feel guilty for not enjoying my time with my newborn :( Has anyone experienced this and how long did it take for you?