I am sedentary, how many calories to eat per day?

my mom finally allowed me to go on a low calorie diet instead of DR Atkins. I told her that diet don't work for me no more. Thank God! I get some apples soon,! Yay! and raw veggies, O after eating nothing but meat, i am excited.I say stop being a cow killer cause edamame is awesome! I am large, over large, my back is being destroyed, my thyroid went out, now it's ok ,but lord I cannot walk. muscle spasms and severe pain in toes legs arms face neck, wow! Just sitting, oh man. I am a mess.{ causes unknown}sciatic severe damage. I need really really easy exercises that can be performed on my bed, that will not cause muscle spasms.standing is not an option. My hospital bed is tempurpedic. Suggestions anyone?