It is time to make the break from your mother. She isn’t as interested in your well-being as she is in control. Taking the job, finding good childcare, and getting out from under her control should be your priority. Where your children get childcare is for you and your husband to decide. If she won’t see your children at all if you don’t do it her way, then this will be her loss.
If you are worried about the degree to which you may be struggling emotionally it would always be acceptable to go for a psychological evaluation by a psychiatrist or clinical psychologist. But the situation you are describing here is a matter of of your mother believing she can threaten you by not caring for her grandchildren. You and your husband need to do what is best for you and you family — not what will appease your mother.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral