Hi Girl,
Does it really matter what you call it? You are miserable and becoming worse through jealousy etc.
Being a mother is the hardest job in the worl. Mother of three so young is a tremendous weight and you work as well.
You do need time away from the children, as we all do. You need some adult social interaction, some different things to talk about etc.
I would certainly suggest you go see your doc and talk about a diagnosis. I'd guess a referral to a therapist would be the best bet right now but either way, you need help with looking after these children. From your husband, from the docs and anyone else you know. Just a visit is often plenty to keep us feeling like we are alive for reasons other than chold care.
Good luck and I wish you well.