Could i be pregnant? :/?

I had unprotected sex on the 26th of January, it was the first day of my period so was only light spotting during sex... i was on my period for 6 days as normal.. But what i want to know is what are the chances of me being pregnant? and when can i take a test to find out? do i have to wait until my next period to see if im pregnant? I already have a 6 month old baby and am just worried... i havent spoken to my other half about this either as i dont want to worry him if im not pregnant... Any advice wpuld be much appreciated Thankyou x