Just started Depo-Provera. Did I have unprotected sex too soon??

I received my first Depo-Provera shot on Friday the 17th. I had unprotected sex & my boyfriend ejaculated in me on Tuesday the 21st (4 days later). I read online that you should use a condom if you get the shot over 7 days after your period (I got the shot 2 weeks and 2 days after my period started). My doctor didn't tell me about this 7-day thing and it wasn't written in the info pamphlet that comes with the medicine either! 

Basically, my question is: was having unprotected sex 4 days after having my first Depo shot too soon? Thanks so so much! 

Thank