Ranks banners is not showing up

i got my rank last season for gold 5. when the season ends, i got gold 4, because of the update that is no more rank 5's. so when i got my rank, i have my rank banner on my loading screen(so happy). but after like 2 or 3 weeks. i started to play rank again just to climb more higher. but i failed and drop all the way to sliver 1. and the next time i play a game n the loading screen, my gold banner is not showing up. i really don't know why. if anyone have the same problem, plz share ur comments. (also, idk if it matters if i am using a mac book air)