Sleep went to 💩

21 months here. Don’t know what’s happened the last couple weeks but every nap and bedtime is a fight. I’ve tried rocking him, co sleeping in my bed, crawling in his crip with him and just letting him CIO in his own room. He will legit cry for 40 mins before he goes to sleep. He’s need are met he’s got a full belly clean diaper and his cup. He’s been getting teething medicine in case that’s the issue. He’s on a schedule and solid bedtime routine. Idk I’m just at a loss. I’m so damn tired of the crying around sleep. Is it teething or regression who knows I just hope it ends soon