yeasterday i was injecting my triceps with some test.I did aspirate at first and there was only air coming in,right in the midlle of the injecting i decide to aspitate again , just out of curiousity, and the syringe filled with blood.I really freaked out , cause i 've already injected about 1.5 cc and i thought i did it in a vein.Well ,nothing happened , but since then i'm really nervous when i have ti inject.Has this ever happenned to any of you? What might 've happenned?