My 3 month old boy also had his vaccination 4 days ago n had mild fever for a few hours before his temperature went back to normal. He also have been drinking less these few days. Perhaps you can try massaging his tummy or get him to do bicycle kicks to get the gas out.
Try to feed more frequently but lesser each time? Sometimes excessive crying can cause gassiness too and gas can lead to pain and thus more crying. It’s like a vicious cycle.
My LO faced that too, although I didn’t attribute it to the vaccine. She just had very bad colicky pain. Ridwind and Ruyi (Yu Yee) oil helped her through that period
My 3month old boy, is facing the same issue. He had his vaccines last Thursday. Applying Ru-Yi Oil & giving Gripe Water.
I gave 2.5ml of gripe water and massage my LO tummy before sleep. It helps for her too. She experienced the same thing too
Mine drinks lesser (volume never go back up) after the fever from 3rd month vaccine.
I had it last time too and it went on for months
Normal!