L.Y.
Hi C.,
If you start having any shoulder pain, cramping in your side (and it will probably be worse than any normal cramps that you have ever experienced), nauseated...then go to the ER (don't just pass it off as being cramps...better to be safe) because it could be ectopic. If those things don't happen then your body could just be resetting itself. It seems to happen and i know...totally weird. Since you're only 28 I doubt it's perimenopause or early menopause but there is always a chance. And make sure you don't miss your next pap and pelvic exam to be sure nothing is going on.
Good luck.