Wondering…

Has anyone experienced this? My period started this morning (as expected) and was fairly heavy. By the afternoon, it had slowed to spotting. At this time, I wiped (sorry, I know it’s gross) and there was a LOT of clear mucus. I know that this mucus is usually present when I ovulate. I’ve had a little during periods, but this was a very large amount. The period was gone until this evening. Now it’s going again and my breasts are swollen, very sore (my nipples are also swollen and very sore). In fact, I put my bra back on because they were so painful without it. Anyone have an explanation for these symptoms?