This seems to be a common problem for people coming into fighting games, focused more on wins, losses, and rankings instead of your actual skill as a player; you can win as many matches and be as high a rank as you can, but none of that is indicative of your actual skill. I know this because I went through it myself a few months back after one too many online sessions. I was absolutely livid, screaming at the top of my lungs and everything and blaming the game for my losses. So what did I do? I took a break, went over in my head what I could improve on and ultimately realized that I was nowhere near as good as I thought I was. After doing all three of the above and spending some time doing genuine training, I saw a significant improvement in my game. At the end of the day, its just a game but what kept me from quitting was my pure love for BB and playing it; I knew I could improve my game, but I had to work for it and acknowledge my own weakness, it was the only way to break through.
Even now in CP, I'm still losing, a lot. In fact, I got 5-30 today in the Arcade Lobby. I felt like shit, especially since I'm generally regarded as the best among my small group of friends I play with so naturally that went a little to my head and today felt like a wake up call. But that's ok, because it reminded me that I still have a lot to learn and it gives me something to work towards.
In short: Climbing the tower is a long, difficult process. You'll bleed, you'll cry, and you'll wonder if its even worth it. But remember why you started climbing the tower in the first place, never lose sight of that. Don't assume it'll be easy, and that its going to be a cake walk, because its not and the minute you start thinkng like that, you'll get down smacked down hard. Mentally prepare yourself for that, be ready to get hurt, but be just as ready to get right back up. Anything worth having takes effort, but you gotta be willing to endure it.
...This was probably the longest post I've made on this site.