Help! Cream tastes foamy!

Whipped cream will be foamy. You whip cream to add air to it. It's also not a great thing for decorative piping. If you add powdered sugar in as you're whipping, it will be a little more stable, but I wouldn't count on roses lasting any decent amount of time. Of course always use a cold bowl to whip in.

You should ask the bakery what they are using so that you know you are trying to replicate the same thing.
 

As Nicholas said, you are introducing air to the heavy cream, thus making it foamy. Adding sugar would add some stability, but if it fell apart that might be a sign that you overwhipped it.

Most likely, your bakery is not using whipped cream.

btw, I am a current student at Le Cordon Bleu.

Actually, whipped cream should not feel "foamy" which implies loose larger bubbles - that's what it feels like if underwhipped.. Foamy is like shaving cream when the gas is finishing in the can- runny and bubbly.  It should be so dense, the bubbles so small, that it's like shaving cream from a new can, just shaken and squirted.    It should feel soft and creamy.  It should hold its shape.  But it won't make roses.  You can decorate with it, i do all the time, with swirls using a large tip with zigzaggy edge or a smaller round tip.  You can write with it.  but not roses, which require a very dense frosting that will hold up without resting on the petal below.  . 

If you want a more stable whipped cream, make italian meringue and beat till cooled to room temp, then whip cream and fold in.  Or beat some cream cheese, then beat in the sugar and then the cream in a thin stream and beat till it makes peaks, and it will hold up better.  I still don;t think you'll get rose petals out of it.  it's too heavy and too wet.