Crying at naptime!

My son turned 7 months on Thursday and every time he gets tired during the day, he has started having a meltdown. He cries if I hold him, he SCREAMS if I put him down and I'm at my wit's end. I don't believe in cry it out, but I'm at the point where I have to just put him down and walk away because I get SO frustrated spending an hour fighting him and having him scream in my face trying to get him to nap.

What is going on? Mamas, what should I do? He doesn't throw a fit like this at bedtime.