I can't seem to add a headline to my post!

A question for women who've given birth, explain to me what is feels like to have a contraction.

Today I felt a pain that was so great and so foreign I wondered if it was a contraction. I am only 26 weeks so this was kind of scary and I've since spoke to a doctor who told me that it likely wasn't because it only happened 3 times over the span of a few hours. That is fine and I'm not going to argue with an expert but if what I felt wasn't a contraction I am so afraid for what is to come. The words I would use to describe my pain today would be burning in my belly but mostly on the lower sides, not in the center, sudden nausea, hot flashes and sweating, my stomach was hard like a rock and I felt like I needed to shit. These feelings lasted for a solid 30 seconds then waned for a few minutes lasting a total of about ten minutes. After the worst of it I drank water, ate some bread and fell asleep for 2 hours. It was in the midst of it I realized I have no idea what a contraction actually feels like and I won't until they really happen. After asking a few friends I've gotten such a wide variety of responses so I am wondering what everyone else's experience have been. I'm just curious.