Instacart some candy. I think if you click delivery tomorrow it’s free shipping or a reduced cost
Seems like general depression or maybe postpartum more than situational since you could now buy candy and make a time of it since you said you enjoy that. Things feel way more overwhelming with a baby. I feel like your husband shouldn't be weird about you wanting to take your baby trick or treating just because he has to work..I would talk to him about that and how lonely and sad you'll feel cooped up when you could bring your baby out to have a good time and lift your spirits. You'll also probably get cute pics and memories of baby's first holloween. I've had to do a lot without my husband. It's not ideal but so much better than being lonely and depressed. I hope you can find it in you to take charge and turn it around and have a good time!
Baby will probably love passing candy out! It will be a big peekaboo and trick or treaters will love seeing your baby - go get some and enjoy your time! :) take the pics for yourself too in the costume