new food gave diarrhea and glassy eyes?

One of my cats started having diarrhea early tuesday morning and it continued all through the day. I gave him 1/4 of an anti diarrhea pill my vet prescribed another cat a few months ago (she's alot smaller than him but i gave the same dosage). I gave him 2 pills yesterday and a pill this morning since the directions are to give twice a day. I came home today and his stool was a little harder. I also switched food. Last week i started giving my 3 cats Purina One, so i switched back to my usual Authority Indoor (sometimes hairball formula). So tonight he's acting different. He's usually really dominant, he's always terrorizing the other cats and jumping on the highest things in the house. He's been good. And he's having trouble jumping on the kitchen table. (Not that i encourage that but i was trying to judge how he was feeling). He's also being really "mushy", rubbing all over my legs, marking me, purring...not usually like that. He keeps putting his face in the dry food bowl but doesn't eat, so i think he's hungry just doesnt want that, but im scared to give him anything liquidy. His eyes look glassy, i don't know what that means. I'm bringing him to the vet tomorrow morning, but does anyone have any idea what it might be or anything i should i do until then???

keep a close eye on them and if it gets worse go to the ER

Yes take him to the vet first thing!

Just wondering, did the diarrhea start when you switched foods?