depo shot

Ok so I recently got on the depo shot at the beginning of October and I still have not received my period and I have been having sex but we have been careful mostly with condoms but sometimes just pull out due to me missing my period I went ahead and took a pregnancy test and it came out negative so what I want to know is how many have done the depo and how it affected their period is it normal to lose it right away or bc of when they gave it to me in my cycle will my period just be insanely late?