Childhood horror

When I was around 10years I experienced a horror. It was a summer time we were playing at night although it was raining so we stop playing and decided to go back home. Me and my Friends were full of mud on our body. We went to washroom, it was open near to lake which was polluted. Our parents used to say us that at night 10pm no one use to go out to washroom alone because it was outside house. Me and my Friend did not bother and went near to washroom. After reach there we found someone is already present there. It was a woman wearing white cloth. Her arms and legs were not visible so, my friends got afraid and decided not to go near of it but I tried to excuse her. When I look back my friends have already gone I was alone there. Even I got afraid all alone there. I ran without looking back and reach home.