BMR calculator, is this anywhere near accurate?

HI everyone.

I'd have a question for you. I'm planning a diet and my dietitian said that I need to start counting all calories. Being a total newbie this sounds like rocket-science to me. Now I know that foods have calorie information on packaging but I just feel like this is impossible to do accurately. What is more my BMR is "only" 1768 calories (BMR calculator). I feel like everything I eat has more calories than what my BMR is. So my question is this - can I go with BMR number (and count in the calories burnt during activity /walking, exercising) or should I totally to ignore that number?

I would appreciate your opinion on this.