levels normal?

I have used my partners blood sugar testing kit a few times and was wondering if my levels were normal? since they appear some what low.

The first time i did it today i was 3.6 mmol and then i tested an hour or so after eating food and it went upto 4.1 mmol and is now back down to 4 mmol. I have actually been lower than 3.6 mmol before now and rarely much higher than 4 mmol but usually between 3.3 and 3.6 mmol before food.

I do have a quite fast metabolism and often skip meals and or eat junk, not sure if that is related but i'm guessing so.

Thanks, just a little worried since they seemed low and lots of websites give different figures on what normal blood sugar levels are.