Car will start but don't say running

Yesterday I change my oil and right before I was
almost done it started to rain it was only raining
just a little but I think I cover the oil good enough to
hurry up to finish the job got the job done then
went to start it and drove it about a mile and a half
and stop at the store then came out to start it back
up it's started regularly then went home 2 grab
something out the house get back in the car it
started up again got halfway down the street and
the RPMs started going up and down as if it was
possessed by a ghost and started to stall out
pulled the car over start it up again it started but
cuts out when I try to start it the RPMs goes from
one and dies out as if it's not getting any gas can
you please give me an advice and helpful
information