Colic??any answers help!?

our pony has been down all day laying down flat..I got her up and walked her around,we called our vet he said if she starts rolling call him back,no rolling has happened,she got into some corn awhile ago 2 weeks ago idk,she looks at her belly,I thought the corn gave her gas build up which has caused colic like I've read,now she laying down,we check on her and have her get up every hour,is this gas colic??