When you play two games at a time you typically get higher skilled opponents as you go until you start balancing out. It all comes down to which you are more comfortable whether you should do 2,3,4 or 5 (1 game unlocks at thirty unexpired). That being said playing two games at a time will probably give you a more accurate rating while 5 typically inflates your ratings until you finish games against better people down the road.
As far as your run and why your rating may seem low.
Shinobi defeated FiveStarGeneral 14446147 11/20/2017 16:42:14 Shinobi: 1364
Losing to a 1364 ELO is definitely enough to bring your score down for some time
NZPhoenix (AHOL) defeated FiveStarGeneral 14444211 11/18/2017 15:55:52 NZPhoenix (AHOL): 1156
This is probably where the real damage is though, as you kinda got unlucky. Phoenix (Boston as he is known to the community) is a 2000 ELO player in real skill but boots alot. He didn't boot in your game which hurt you a ton and that loss will drag you down until it expires (or boston goes on a run while having his boots expire which is unlikely).
Poor play (especially picks) hurt you early on, but looking at your other games you're improving and making better picks, which is a good sign for you towards the future.
Anyways, good luck, and hope to talk sometime!