Was it bad for your LO?

T was 10 days early birth wise. Literally overnight at adjusted week 51, he started whining a lot, fussing, demanding more, is harder to please, and is showing signs of separation anxiety. It's been going on for 3 weeks now. In between all if this, he had 12 month shots, a cold, then a fever. We also started cows milk by the fussiness preceded the milk by 2 weeks. I just want my happy go lucky boy back! I hope/think these are developmental issues. Hes working on walking and aeems to be trying to say more words. I hope it's over soon!