That is the definition of life with small children. It hardly seems possible that you can get time for yourself. One idea that comes to mind are Mini-Meditations.
Identify 4 super repetitive times in your day- like when you’re changing a diaper, waiting at a stoplight, folding clothes, stirring soup, waiting in a drive-thru lane… and dedicate that time to some positive affirmation for yourself.
At the Stoplight: I’m doing OK right now. I’ve got what it takes to take care of my children. I’m stable and safe. I proceed with caution because I’m moving with others.
Folding Clothes: Now is the moment. It’s all I’ve got. I’ve folded these shirts before, and I’ll do it again.
etc. etc., can you add some other suggestions?