Mommies I need advice! My son is generally a happy 4 month old, but the past few days he has been…

Mommies I need advice! My son is generally a happy 4 month old, but the past few days he has been super fussy (fighting sleep, not eating right, crying). It all started after he got his shots, he got a fever and threw up. His fever is gone but he's still super fussy and it's been 4 days. His belly is making all kinds of noises so maybe his tummy is upset? (He's a little gassy) He cries when I try to feed him (he's breastfed) and he tries so hard not to go to sleep. I don't know what to do to help him.. any ideas?