Wat ovulation kit shows if I m already ovulating. I tested on 11 day it was +ve. On 13 day it is -ve. Wat does it mean?

Early surge. It likely means your lh surge occurred on day 10 or 11. This is in the normal range.
Normal. It is normal for the ovulation test to be detected for 48 hrs after which it fades away or disappears completely. What is being tested for by the ovulation kits is a hormone called lh that surges to cause ovulation. The level then drops after the surge. It is therefore not necessary to check your ovulation kits once a positive result is seen as it will normally go away in approximately 2 days.