Well, I've merely reached 1900 this season, so I'm not considered a pro player, but again, I have my ups and downs. Not only player downs (every human being has them) when you just aren't in mood/can't play like you usually do, but also the bad luck (like I had today, 6-7 shaman-warriors with s3/brutal in a row.....) which can sure drop your rating alot, also messing up your mood for arenas. Tip is to never give up and work on your combo. If other people did it, you can too.
Ofc, as I've noticed, some bgs don't allow many combos due to hard competition at high ratings. Well, that's where you prove if you're a pro, but you can always reach the 1800 imo.