How do I calculate my profit?

That's definitely an important question! You have to multiply the value of one pip by the number of pips you made.

For instance, lets say you bought or sold GBP/JPY at an exchange rate of 148.59 As explained here the pip value for you would be (0.01 / 148.59) х GBP 10 000 = 0.67 GBP per pip. If we assume you're making 25 pips in this position, your profit would be 0.67 pounds per pip х 25 pips in profit = 16.75 pounds.

Now, should we also answer the question "How do I calculate my loss?" ;-)