Metformin

Has anyone had stranget digestive problems sleep while on metformin? I have found 4 foods so far while on it that cause the same thing, tomatoes, lettuce, onions and kraft dinner. I wake up in the middle of the night having terrible constipation. It's as if there is a cork in my butt. Then I have to go on a long walk and or drink coffee to get things moving. To the point of where I know it's comming, sorry for being so graphic, but literally in one stride of walking it's like o! There it is! Then holding it till I get home, then it's diharea at least 2 times after that. It's quite the nightmare. Then of course because of the walk and coffee I can not sleep. Making school and work quite challenging, but I am 100 percent sure that is what it is. I cut out tomatoes on subway, it got better, then Lettuce and it completely went away for over a month! Then I ate kraft dinner last night with no Ketchup, figusing it was the tomatoes in ketchup, NOPE, it's the kraft dinner itself! Any other foods that you know of that I can add to this never never ever eat list would be most welcome and helpful! Been quite the nightmare getting 4 hours of sleep every other night for the last 2 semesters of school. Thank you Appius