I had this in August. Went in for my annual pap and exam. My GYN found the lump, but I had just done a self breast exam the day before, and never felt a thing. So the fact that she felt it and I didn't scared me. In fact, up until this appointment my health anxiety seemed to be in "remission". She actually felt a few lumps, but wanted to send me out for an ultrasound on the biggest one. So I got in the next morning to do the ultrasound. They saw the cyst and said it was fluid filled and nothing to worry about - This was a Thursday. But because I was so worried about it, I wanted to get a second opinion so the following Tuesday I got in with a different imaging place and had another breast ultrasound. By Tuesday, they couldn't even find the cyst! She had me show her where it was, and she marked a dot on my skin of where it was supposed to be, and she even brought in the radiographer to scan me because she couldn't find it. And guess what? He couldn't find it either!
They said that if I were dehydrated, my body will try to store up water in my breasts, creating fluid filled cysts. I remember that between Thursday and Tuesday I had been drinking a lot of water, so my cyst could've disappeared because of that.
Or it could've been God's diving healing, because me and the rest of my family were doing A LOT of prayer in this time - so I don't want to rule that out either.
I'm sure it's nothing to worry about hun. My GYN told me that if you have breasts, you're going to have cysts. There's just no way around it. Even men have cysts in their breasts from time to time. It just happens. So chug chug chug water between now and your appointment and your cyst might not even be there! Oh! And pray pray pray too! - Can't go wrong with that one!!!