Clumpy??

Rachel • Son still born May`14, baby girl born April`15, due with baby boy Dec`17

I tried to give my 1 week old a bottle this morning while out but he didn't take it so I put it back in the fridge when we got home. I didn't warm the bottle and it was only out of the fridge for maybe 3 hours and in a insulated bag. I just looked at it after about 3 hours back in the fridge and it's clumpy, I've never had this issue and don't know what's going on. * can't get pic to post