Why??? Our daughter has been waking up at like 2:30/3 in the morning since Saturday and refuses to…

Why??? Our daughter has been waking up at like 2:30/3 in the morning since Saturday and refuses to go back to sleep. She falls back asleep usually about 6:30 and is up by 9 for the rest the day. No naps anymore and she fights sleep until 9/10 most nights.... We've tried putting her back in her bed and I've tried rocking her back to sleep, and even letting her into our bed but still no luck, she's not quite 2 yet and idk what to do