Hi normally my period is very heavy but this time I've been 10 days late and my period is super light and brown. I'm a little bit concerned as its the very first time that im experiencing such a light and brownish flow.

Check a test. There are many things that can cause your period to be late but,if you have been having unprotected sex, the first thing to do is check a pregnancy test and repeat it in 3-5 days if it is negative. Some medications including contraceptives can cause this too. If the tests are negative, see your PCP or Gyn for a complete history, exam, and appropriate testing to find the cause. Hope this helps.