Am I A Horrible Mom?

My 9.5mo has been unbelievably cranky lately. Everything is the end of the world to him. Playing is fun for a second then he throws his head back or down giving up and crying. Throwing tantrums like a snotty toddler! When he's obviously cranky, hungry or tired he won't cooperate. He knows what he needs and wants but everything seems to make him frustrated and MISSERABLE! I try several times to help him BF and calm, help him to nap. He struggles and screams and wiggles out crying. After three times I just put him in his crib and let him freak out 5 to 10 min to tire himself and then succeed at feeding to nap. I try! He just is miserable and making me miserable. I have no choice at a certain point but to let him freak out and tire out. Every few minutes he's screaming or crying about something and isn't pleased for more than a few minutes with anything. Not even the things he loves the most. He's notsnt teething. He isn't sick. No fever. No diahrea or allergies or anything. He just had a check up. He's in a developmental leap. Emphasis on mental. I feel horrible but he's constantly complaining and I'm sick of it! I just can't wait for him to go to bed!