I think I know exactly how you feel OP. (And I had a husband home by 6pm and babysitters etc.)
Many yrs ago, I had 3 under 3, which was a handful. I felt at times really lonely and terribly bored. Was not able to relax, read a book or anything fun like that! Seemed like I had to find a way to just get through each day, with the house in tact and everyone alive and clean/fed! (A real grind!)
It's quite hard to suddenly find yourself as a sort of personal "slave" to your kids, especially after you had a career. There's no "me time" for you at the moment, and we all miss that.
Could you afford a teenager to help you out?
I found a lovely 16 yr old who was happy to help me out for a few hours each weekday morning, (in her school hols), for a while ... and it was honestly great just to have someone else/new to talk to! (As well as some physical help.)
Going back to work would solve some problems, (ie your lost sense of identity/lost financial independence/lack of adult contact etc), but would create others, (cost of good childcare, what happens when kids are ill or childcare falls through, finding the pressure at work more than you can cope with on top of worrying about the kids/cooking etc), so there's no magic solution.
Could you try instead to look at your position as a sabatical to build up your core skills? Then just praise yourself for managing to be the best mum you CAN be, in spite of the fact you are actually trained as a lawyer?
Let's face it, if you were brilliant as a childminder/kindergarten teacher, you would have trained for that and not done law? So you are probably out of your comfort zone? Just as a childcare specialist wouldn't necessarily find being a lawyer easy or fun?
Bringing up your own children is part of the reason you had them, otherwise you would have had them adopted ASAP? So try to not beat yourself up about not finding it easy at the moment ... & just push on? (You are not alone!)
I'm sure you will find it easier once they are older and at school/reading etc.
For now, keep trying to get out & about, to meet more people if you can, just in case you spot another mum in same position who you could identify with/share some of your time with? (It DOES help to find a good friend or two!) It might happen or it might not. But there's always hope. And mumsnet!
Eventually, you can think of going back to work, but make sure you are truly ready, before jumping out of the frying pan into the fire?!
In the meantime, agree with other posters that you need to try to find some time to do your own (leisure/intellectual) stuff?
Hope the empathy helps a bit! (My kids are grown up now and I don't regret any of the time I spent with them!)
Good luck!