I just had a haircut and they used thinning shears on me. Will my hair grow back normally?

I had long, thick, slightly wavy beautiful hair. A friend suggested thinning shears, so I asked the hairdresser to try it, but I don't like the result at all. My hair is 3 inches shorter and thin from the back. I'm really afraid that it will not grow back how it used to before :(( and ever since the haircut I've had hair falling out even after shampooing it (since yesterday). I'm really scared! any advice is appreciated!