Things like this are why I don't think online slots are truly random. I think the game providers break everything down via sessions and track your winnings.
When you 'log in' to a game I think it pulls up info on your past winnings with that provider and decides if it wants to give you a winning session or not and bases everything around that. Because I've had big wins on games and then no matter what other games I play they will all be dog water and not payout anything until any previous winnings get 'paid back'.
I'm on this kind of streak right now with playngo. Last month I did very well on them, this month, every bonus has paid under 20x and that's if I can even land a bonus within 500 spins.