3 games is far to low to be considered a streak
I'm going to have to ask you all to really up your standards here. If you don't play a hundred + games, don't expect your MMR to be exceptionally accurate to your skill unless your skill happens to be dam near the MMR you got placed at. if you play 100 games your setting 3% as the starting number for a streak. Working in sets of 3-6% is not really Rapid, its a pretty minor #. You'd need to have 16 different streaks to hit 100 wins even at consistent 6 wins and 33 streaks to hit 100 wins at 3%.
I don't get how folks feel 3 wins or losses is a relevant enough number to be considered a streak. I suppose my Bias is I'm thinking a streak would be defined as "move very fast in a specified direction." Then "a continuous period of specified success or luck." Thou even if you use the latter I still don't it as a really relevant period of time.