I’m an introvert and have kids full time. I have a 7&8 year old. It is a struggle, but they are also young enough that not feeling affection and love from you could be really hard.
I would really try to look at that time with your son as being your exercise to go beyond yourself and be the good mother your son needs. He’s not with you full time 24/7. You work full time, and he has school and lives with his dad every other week. That’s not a lot of time with your son, but you want less? Or do you want coping skills to handle your limits with your son? A better therapist can help you.