Is my garter pregnant?

[SaytaSora]

This is Houdini! I caught Houdini in the wild a few weeks back and have been feeding him pinky mice every week (the pet store said it should be eating hoppers but Houdini won't eat anything with fur on it, so I've started doing 2 pinkies instead). Originally I assumed Houdini was a male, but it turns out it might be female and mating season season occurred before I caught the snake so it's entirely possible that I currently have a pregnant female. So here's 2 pictures of him/her, the tail was cut off after an injury in the wild, so if you need a picture with the old tail I have one. Can anyone guess if its male/female and if it's possibly pregnant? I heard that you should feed pregnant females more so I was just wondering if I should or not. Thanks!