We had the most happy, sweet boy that slept like a champ and ate like a champ. We could take him out to restaurants with us and friend's houses. He slept through the night. He was wonderful and playful and happy. Then all of a sudden, he is miserable all the time. He is only happy for brief periods of time before whining and crying throughout the day. He is up multiple times a night. He gets frustrated about not being able to sit up, roll back off of his belly and pretty much everything. He is still eating and gaining plenty but he fusses through his meals. He is 4 months and 1 week and he has been getting progressively more unhappy since about 2 weeks ago.

What I do know:
He is teething (per the dr) but his teeth haven't popped through yet.
He is making big developmental leaps- he is learning to roll both ways, laugh, is starting to sit, found his toes, is grabbing everything

Did anyone else's LO go through something similar at 4ish months? Will it pass? Or is this the new normal? I'm tired and frustrated and feel terrible for him that he seems so unhappy.
HELP!