How Long Does This Injection Stay In Your System? I

How long does this injection stay in your system? I had a shot of it three weeks ago (40 mg.) and am having problems with muscles aching and feeling tight and, feeling like something is running inside of me. I also take Xanax and I thought it was withdrawal from it but I am not sure what is going on.and blood sugar. Monday was a horrible day with internal tremors, but yesterday was a good day. Today is terrible with muscle problems and internal tremors. Thank you for your help!