Ok, I believe the process of removing the battery, place it back in, hold power and volume down till clockwork appears. Sometimes this works and sometimes it hasnt for me. If you did a data wipe factory reset (which I dont believe you would have need to in order to just flash a new theme for a custom rom) then sometimes this prevents you from getting into clockwork. Ive been lucky on some occasions getting into clockwork by like the 27th battery pull, dont ask how or why because I do not know. if worst comes to worst you may have to sbf flash and i could walk you through.