is my outdoor stray cat prego?

this stray cat had been sleeping in my greenhouse for a long time (about a month) so I started to feed her and since then she has adopted my front porch. This was back in April. She's always been a very skinny cat. (i'm amusing bc she was wild) But when i went to pick her up the other day she was very heavy. She looks fat too. Am I feeding her too much or is she pregnant? I can't check her nipples because she hates it when i touch her tummy, she always has. And if she is pregnant, what do i do? I am not aloud to bring her inside as i have a dog and he hates her. Bringing her inside is not an option. And if she does have kittens she will probably have them under my green house because that is where she goes when shes scared its dark and small. Do I give her a cardboard box? What do I do help!!!!