I have always been best friends with my cousin and we try to see each other at least every month, usually at his house because we have a group of friends in the area. For the past 5 years we have been going down to a nearby circular lake that feels as if it is completely isolated from the world, for the past 5 years that we have been going we have never ever seen anyone else go there. This lake is amazing during the summer, the scenery is vivid in colour, the lake is always clear and occasionally you can see rabbits darting through the trees. I won't say its location for privacy reasons but it is one of my favourite places to visit during sunset, the skies glow orange and purple as if from a scene in a book.
One day last year I, my cousin and 3 other friends decided to go down to the lake to hang out, we spend an hour just chatting and was then about to swim in the lake (which we have done so many times) I was last to get in because I was a bit busy on my phone. Everyone swam off to the other side of the lake and were splashing about and I heard someone calling for help so I looked up from my phone and saw a young woman splashing around in the lake calling for help as if she was drowning. The first thing I did was shout out to my cousin about it but he just looked at where I was pointing to and looked back at me and asked what I was talking about. I looked back to where the woman was and she had disappeared right in front of my eyes (this is not the first time I've seen something disappear in front of me).
My friends thinking something was wrong decided to swim back and get out to see what I was going on about, I explained to them what I saw and they were clearly freaked out by what I was saying, I insisted that we walk around to check the area and so we did but to find nothing.
I'm convinced that this woman was a ghost or apparition because: 1) my friends would have heard her 2) I'm sure water wasn't splashing around when she was splashing her arms around 3) people do not disappear into thin air in front of your eyes. My friends went home and my cousin and I didn't really talk much about what had happened, later that day we drove back home after our visit. I chose to accept that I saw something strange that day but I wasn't going to admit to myself that it was a ghost or premonition; I think that it was just my imagination or just something unexplainable.
This event happened last year and I have since been back to that lake with my friends, we never talk about it, in fact it's as if it never happened because it wasn't a big deal to them, so far I've never seen what I had saw again, but I never go swimming in the spot that I had seen it happen.
I have never had any bad feelings about this place in the five years that I had been visiting, but out of nowhere it had happened, could anyone tell me why it has happened at that time or what it means?