@Rachox is correct when she says that an OGTT can be raised if you have been eating a very low carb diet in the days beforehand, simply because your pancreas has been used to being allowed to produce a lot less insulin. Once you hit it with 75g of pure glucose during the OGTT it is still asleep, producing very little insulin. It needs time to wake up, hence a raised 2 hour reading. I don't know if this was the case with your test.
Can you please guide me bit more about low carb diet I am also doing intermittent fasting and literally avoiding carbs completely. Should I continue the same routine or adding carbs would be more beneficial?
Do you mean you are avoiding carbs at all times, or just when you are fasting? Avoiding carbs at all times would mean restricting yourself to meat, chicken and other fowl, most but not all fish, most but not quite all fat. Is this really all you are eating?