This is a common question, and it's very difficult to answer with any accuracy.
First, have you been answering questions in under 2 minutes?
Do you answer dozens of questions in a row to simulate the endurance component of the GMAT?
Do you typically spend an hour completing 2 AWA essays before you begin tackling math questions? The energy spent on AWA can cause fatigue and affect your math score.

There are other factors that I haven't mentioned here, but suffice it to say, the best way to gauge your math abilities is to take an official practice test (you can download the free testing software here: https://www.mba.com/the-gmat/download-fr ... n-software)

Cheers,
Brent