It is impossible to tell whether you're playing well based solely on your results. The very large variance in BJ allows for terrible players to win sizable amounts of money in the short run. I frequently play practice games against a "fake house," if you will, with friends that are some of the worst BJ players to probably ever play the game. Yet, the variance will often allow them to win, win, win, for hours at a time once in a while. When your max bet is $150, it is quite common to be up by over $600 during a session, even if your basic is less than mediocre.
Let me tell you one thing though. You WON'T beat any 6-8 game in this world with basic strategy alone (over a significant period of time), unless the casino is running some kind of promotion like paying 2:1 BJ. Other tactics, card counting in particular, are necessary; it is not enough to know the statistically favorable play in each situation (assuming fair composition of the remaining decks).
Best,
SP