Is it possible to over whip the buttercream?? I tried a new recipe because I needed a small amount and the buttercream became very watery..did I over whip it and broke it down?? Has this happened to anyone else???

I don't know your recipe, but usually if you overbeat buttercream (especially if whipping on high speed with the wire whip instead of the paddle, and if the beater/paddle isn't completely covered to the top of the blade), it becomes airy. Maybe your recipe has too much liquid. Is it just watery, or has it separated?

Another possibility: If the meringue is not completely cooled before adding the butter, the butter will melt and it will never come together.

i used the paddle atachment and no meringue was used...=(

the first time I made a butter cream I have it well done, the second time it was a true disaster too thin in the third temptation, not at all successful, I would like some advice please, because I am new to this area! thank you for your help it would be really good!