Intense waves of pain

So yesterday i woke up with intense stomach pains. Not abdominal but my stomach. And not i have to use the bathroom but, like someone is stabbing me. About 4 days ago i got the Tdap shot. Im going to be around my newborn niece and just needed to get it. Now im having these crazy pains. It gets better when i eat, but doesn't last long. I know what you're thinking now. Im probably just hungry, but with my schedule sometimes I could go a whole day without eating. I know thats not good but i can. So what the hell are these pains. They come in waves and just make me want to curl up. I can eat at 10 and by 4 im doubling over in pain