Stalling in quadcopter

2 days ago, I was flying my home made s500 quadcopter with APM 2.8 flight controller. There was lot of wind blowing that day. My quadcopter was hovering (Although it was hard to hover at one place because of high wind) and suddenly osd showing in my fvp goggle that quadcopter is stalling. I was installed the minimosd with my quadcopter on that day and I never had this experience before installing osd, So I wanna know that what would be the cause to stalling my quadcopter.