Is my cat pregnant !?!?? or is she just eating too much ?

My cat Abigale is maybe 1 year old . She spends ALOT of time outside, And now her tummy is really big . there are no lumps, but its hard . She is very affectionate (like ALWAYS) but one thing, like 5 minutes ago she started ripping up the chairs . She has never done this, aand when I picked her up she meowed (I didnt grab her tummy) Youd think she is pregnant, but I think maybe its an eating disorder (For cats, I know, but shush) She keeps eating and eating and eating, Abby will NOT stop eating !! Is she pregnant or is this just because shes eating too much ?? Oh and is there any diseases that might cause a huge belly ?BTW None of the rest of her body is fat, she isnt a fat cat but not a slinky slender catt, either .