just wondering I had a birth implant in my arm for 2 1/2 weeks now and I haven't been really…

just wondering I had a birth implant in my arm for 2 1/2 weeks now and I haven't been really hungery. I only been eating once day and that's at supper time and after I eat I have a very bad tummy pain and feels like I got really bad cramps (just got off my period since last night) but other then that I haven't been in the mood of eating. has this been happening to anyone else.