Fuel breaks down oil and causes excessive engine wear.Change your oil and monitor oil level if it increases and is runny again you have a bigger problem.i would also change pcv valve and change valve cover gasket if you removed the valve cover.
it is normal for some gas to get into the oil over time.you start a cold engine it will run rich and any unburnt fuel can get past the piston rings being gas is thinner than oil.this is common in cold weather and lots of short trips where you don't let car get to operating temperature.