Been on TRT about 2 years, only been self injecting a few months. Had issue for 1st time and wanted to run it by the forum. I injected air that was about the equivalent of my cyp dose into the vial, pulled back on the plunger to load the syringe and the suction strongly pulled the plunger back in. For the 1st time I had to fight the plunger to pull back enough to load the syringe. Same draw needle size as previous times, same amount of air injected. Any idea what was different and why the plunger was so difficult to pull back?