Elishia, I feel for you. Our last two weeks has been identical. 3 hour wake ups adn just screaming. In fact, last night I reintroduced coco's dummy at bedtime and she SLEPT THROUGH!! Mind you , I don't encourage dummy if you aren't using one.
I would recommend calling maybe tresillian, just for some advice. I am heading off to sleep school myself tomorrow, and would probably recommend that.
However, I also gave Coco a dose of worm medicine. That might sound weird, but DD1 thought she had worms so I treated coco. The signs are irritability and unsettled, particularly at night. Probably worth checking (do a google search of what to look for). It's a long shot, but you never know.
Other thing is that it's a habit. Does she have a comforter of some sort? Maybe a sheet or toy would help (or last resort, dummy)!!
very best of luck xoxox