Bad mental day

I'm having such a bad mental day today. Idk what happened, I just woke up not ready to deal with my 6 week old daughter. Like I let her fuss for like a half hour while I sobbed knowing she was probably hungry and needed a diaper change and I feel so awful about it. She sleeps in her bassinet at night but won't during day and she only stands the carrier for so long so I'm basically holding her all day. I'm sure it's a bit of burnout but obviously there's not much I can do except suck it up. It's just one of those days where I'm really regretting being a parent and that thought of course just makes me feel worse so I feel like I'm spiraling. I was able to get her to sleep for a 3 hour contact nap and figured I'd try to put her in her bassinet so I could ya know take a shit and eat something and as soon as I put her down she woke up. I went to put a binky in her mouth and made the mistake of saying something and at my voice she started smiling and giggling which made me absolutely lose it because how can I walk away from that?? Especially knowing it would make her cry leaving her so I can do some things ☹️. I've been doing mostly okay mentally with a few little breakdowns but nothing like this so far. I already struggled with depression but this is like "I just want to close all the curtains and lay in bed and sleep all day" depression... ugh.