Is my pump to small

I just bought my first vacuum pump. The first time using it, I put my erect penis into the tube after lubing it all up. I was able to squeeze the bulb for the pump 1 time and then it did not fill back up with air. My penis was almost to the end of the tube when I did this. I was able to get maybe a sixth of another squeeze and that smaller squeeze felt like it was going to make my penis grow but was unable to squeeze the bulb anymore.