I am sure your mother is well aware that you must be feeling guilty now, and her control of you is bolstered and perpetuated by your propensity to feeling guilt.

Since the guilt is yours, you have some control of it.

You cannot control your mother's behavior, but you can at least try to let go of guilt.

You talk about her age and frailty by way of making excuses for her.

But you are not well, either - you are pregnant and with heart problems. So hopefully you will excuse yourself, first.