somebody help me out

Okay so I started depo April 7 , 2016 . I was spotting then I took my second shot August 12 , 2016 . After that I stopped taking depo  . I stopped spotting in September . I was suppose to get my 3rd shot in October, but that's when I stopped taking depo so I didn't get it . Okay well today is January 2nd , 2017 . I'm spotting its light . Me && my boyfriend had sex last week on Monday ... Could it be irregular period or could I be pregnant ?