Mine was thinning (2.5cm) and really soft and dilated just a tad at 26 weeks. How many more weeks do you have to go? My doctor said a normal cervix at 26 weeks would be long (4cm or so), closed and firm. Softening, thinning and dilating means your body is getting ready for birth. Some moms do this before others, but in my case, 26 weeks was way too early so I got put on medication and modified bedrest. I'm 34.5 weeks now and nothing has changed. My cervix actually lengthened a little. Another 2 weeks or so if everything is okay it's bombs away! I can't wait!
If your doctor didn't put you on medication or order bedrest, I wouldn't worry because he/she knows your symptoms/situation, but if you're not yet to term, I might take it easy a bit, just to be safe. I hardly have any contractions on the medication, but I totally can tell that they increase on the days when I'm misbehaving.
My doctor said BH contractions don't cause your cervix to change (soften, thin, and dilate) but real contractions do. Problem is, usually I can't tell the difference.
Just follow your doctor's instructions and you should be fine...maybe take it easy a little if you're not yet ready to deliver