Agree with a lot of what is posted above bec I’ve gone thru a similar experience.
How do you spank an 11yr old? I would think what would be more painful at that age, at least with my own kids, is to ban something they have use of. A screen or game system like an iPad, Xbox or just the tv. “Hit” them where it hurts & screens can hurt. Lol

If you recall this story to a therapist of what you posted here it can cause problems. It’s a red flag. I recalled a incident I had with my child to a therapist where I was physical and as soon as I said it, I was told not to say anything more and CYS was brought into the picture for over a year. This is one area of zero-tolerance that a therapist has to break confidentiality and get help into your home and I hope into your family. For us it was a lot more problems, but in the long run it did help. We were not expecting this action when I tried to speak honestly in a therapy session.

So please go with your gut and tell yourself that you need to take a break and exit the situation ASAP. For me that meant I was to stand on the back porch and take deep breaths & cool off.

I also agree that sharing your own issues with your kids is a bad idea. I do understand that you want to convey to them that you can understand their feelings, but you don’t want to lose that parental relationship. Children can miss interpret it and blame themselves. They might feel obligated or have a self fulfilling prophecy of MH issues that might not be there. Save it for when their much much older.

Does the school system offer any structure to help. Some have a parental liaison to work with schools & therapists. If it’s a public school like in the US start pesting them for some help.
How about finding a family therapist for all of you. One that will work with you as a group. We had some luck in this area. Our oldest was acting out & I could see where it was effecting the younger ones too. They will be effected too. And yes therapy for you so you have a place to vent & work on your own struggles bec you don’t have that built in back up of a spouse for help. So you need to be more aware of when you need a break before things get to the “red zone.”

Our library had parenting type lectures once a month I sometimes wento & we have one great therapist in our town that puts on monthly parental discussions for “today’s teens,” that’s been really helpful.
Dig into your town & see if there’s anything that will help. Ask the domestic shelters to maybe point you in some direction.
All this effort will help you, your family & even the court system if they get involved, that you’re trying to reach out for services.
Best of luck to you!