I'm sorry you're going through this! That's a large cyst... it's no wonder you've been in pain and can barely move!
The OB may want to do another ultrasound or some other imaging test to check the current size and characteristics of the cyst. If you have a copy of February's ultrasound report, you could take that to your appointment this week. That may prevent you having to have another one done.
Being that it is so large, it will have to be surgically removed. Ask if they can save your ovary or at least part of it (cystectomy versus oophorectomy) since removal of an ovary can impair fertility and even cause an early and more severe menopause which increases your risk for a number of health problems such as heart disease, osteoporosis and dementia (along with others).
Best of luck and please keep us posted.