You are talking about "the law of averages" or the Gamblers fallacy
From Wikipedia:
the "law" usually reflects bad statistics or wishful thinking rather than any mathematical principle.
Gamblers fallacy:
is the belief that if deviations from expected behaviour are observed in repeated
independent trials of some
random process then these deviations are likely to be evened out by opposite deviations in the future. For example, if a
fair coin is tossed repeatedly and tails comes up a larger number of times than is expected, a gambler may incorrectly believe that this means that heads is more likely in future tosses