Oil/Air Problem

At Christmas time I had the master seal replaced, along with every belt in the car and the valve seals. None of this had been done prior and the car had 115,000 miles. Oil was leaking which is why I went to the mechanic. Yesterday I noticed a small amount of oil on the ground and a bit of hesitation in 1st and second gears. I pulled over to check the oil and when I pulled the dipstick out, there was a small burst of air, like from pressure. I have never noticed this before. Anyone know anything about this or had a similar problem? Oh this is a 99 Civic EX (manual transmission)

THanks!