Jack's throwing up

[Sabrina&Jackson]

Hey everyone I just woke up to Jack throwing up and I can physically hear his stomach doing something like squishing around.
This is his first time being on only cat food and I have ketones testing strips coming in the mail here in a couple days. Anyone see this before? Hes eating grass right now.
Crap yall he needs to GAIN WEIGHT. And we're like a hour away from feeding/dosing time.

 

[Sabrina&Jackson]

he is NOT lethargic right now nor does he lack appetite. Honestly right now is the most energetic I've seen him but this is how he usually is an hour from feeding.
ALSO I ran out of fancy feast last night and bought a couple cans of Sprouts Spots Pate so I fed him that last night.
Ugh stressss

 

[Sylvie]

could just be the new food addition not agreeing with him, vomit or diarrhea happens with our cats when we feed something new sometimes too.
if this is only food you have, try just feeding him a tbsp or so every couple hours instead of his normal portions today so it doesn't upset his tummy again.