Depo Question

Cl

So I got my very first ever depo injection on July 26th of this year and was supposed to go back and get my second dose earlier this month (I think on the 11th). However, I will not be continuing on to my second shot due to the extreme side effects that accompanied my first injection. I am curious to know how long it can take for only one injection to wear off and if I should have been taking more precautions as I’ve had unprotected sex two or three times since not going to my last appointment. If anyone knows the answer it’d be greatly appreciated!! Thanks♥️