Can't get my 2 yr. 8month old out of my bed!?

Help! Every night at 2 am my daughter ends up in our bed. i do not even hear her anymore! She goes to bed very late - like 10pm and she still takes 2 hr. naps. I've tried returning her to bed a thousand times and she still comes back. She refuses to go to her own twin bed at night, will not lay there and even try to put herself down. I can not figure her out. I've tried putting a gate at her door to deter her but she cries there for hrs. and wakes up everyone. I've even let her cry until she actually vomitted from all the crying! That will never happen again. I do not know what to do. I've explained it thousands of times but to no avail. Any ideas? I'm losing my mind.