You do sound very angry.
I hope I am not mistaken but is it you who posted about trying to set up a playdate and being frustrated that the other woman didn't reply quickly enough?
Just as an example of why I say you come across as angry:
I have had 2 young kids so I know how hard that is but you do seem super spicy about things that are quite common when you are in the season of young kids. People don't always get back to you in accordance with your exact timetable - they have to first read all the billions of other Whatsapps they get/check with OHs/ask the kids/consider fitting in other things during half term eg dentist appointments/hair appointments etc.
And if you are fair, and less angry, your invitation was very opened ended - "I am free all week". You got good advice on that already but I am not not sure why it makes you so angry that maybe another mum who maybe works full time/also has an unhelpful husband/is just tired and exhausted/is just trying to catch up with herself and will get back to you when you can did not respond in accordance with your specific timeline. Your fixation on getting a playdate for your daughter is a priority for you, and you alone, but not necessarily for everyone else who might be juggling other things.
My overall point is that you do seem very angry - I think maybe a GP chat might be in order. Low iron, as mentioned, is a good thing to check on. As already mentioned, depression can manifest as anger. Hormonal checks might be useful - it's best to discuss all these possibilities with a GP.
Also, maybe it is time to think about how to deal with the "cold and unloving husband" because that can't be helping you at all.
Do you get any time to do something nice for yourself? To de-compress? Maybe you could see if you could carve out some time for something that helps you relax and brings you some happiness / joy.