Try again with an aspirator, buy a GOOD one ( for instance, NALGENE, plastic, very good even with low water flow ) and use it also for filtering, evaporating solvents, etc. Save your vacuum pump for serious work, like ketone.
Also, your oil might be dirty again. I have this problem with my vacuum pump, is a good one, single stage rotary vane, but everytime I use the vacuum degrades, I have to replace the oil. How do I know ? I measure the vacuum with my vacuum gauge. I am planning to add a trap, but I can't do it right now, so I just distill fast, start with aspirator to get out a bit of H2O vapor and other stuff that degrades the vacuum when absorbed in the oil.
Repeat, get an aspirator. Also test your oil, use the FSE.