Don't Give Up!
Sorry to hear about your first outing. These things happen, especially with your bet levels. Just a shame that it happened at the onset. I'll address your specific question and then give my opinion on what happened.
You said, "if anyone has had a similiar experience I would like to know how you handled it." To be honest, I doubt that most here lost at the outset. This is not totally due to skill, practice, or diligence. Simply put, people who happened to win from the get-go developed confidence in advantage play techniques, and were more likely to make it through the losses, having seen the potential. People who lost early on, even if they were perfectly proficient, were probably more likely to quit, for obvious reasons. Note that the distribution of initial winners to non-winners (of equal skill) is equivalent to an individual's single session win-loss probability.
That being said, I did win from the onset, although I had plenty to learn. I won $3000 over three months playing red-chip at a very average 6D game. I studied a lot about the game, and practiced quite a bit. However, due to simple variance, I lost all $3000 over the following two months (300 units). It was frustrating, particularly at my relatively low betting levels at that time. This encouraged me to tighten up my game (tigher wong-out criteria, care in choosing the best game available, wonging in at +2 and no lower, NEVER altering play for comps unless playing specifically for them, etc). The wins did come back. I'm up $6500 since then, and have moved up to green chip. I'm still new to AP, but I have full faith in both the theories of AP and in my abilities, despite inevitable variance.
Now, I do have a couple of comments on your situation. You sound well-versed on the theories of card counting. However, perhaps you'll want to play for at least a few months at lower limits for live practice. You'll learn how your home casino reacts to bet variation (or at least their reaction to bet spreads at lower limit play), how the pit acts in general, etc. IMHO, it's important to learn the intangibles of the casino environment, specifically as it relates to advantage play. I did see a few things in your post that indicate that you could benefit from this. First, it's too bad you didn't get "credit" for your loss. That could have bought you more time than any camoflage possible. Rather than getting this benefit, you may have ended up looking suspicious by refusing to give ID or a players card. I think many of us here would jump at getting credit for a 240 unit loss at our home casino. I'd milk it forever (I'd remind the pit of it periodically, especially after a win, lamenting that I'm still down). This is not a criticism, just an observation that there are some skills that are best acquired through practice. Next, as I mentioned earlier, it's important (I think) to learn how casinos handle bet increases. I haven't heard "cheques play" on 6D for a few months, even when betting $200 x 2 and even when it's being called on other players. Nothing special here -- I'm just a bit smoother now in increasing my bet than I was as a complete newbie (no hurry to change bet levels in 6D anyway). Additionally, I'm careful about when I give my players card to the pit. Give it to them during losing sessions. Combined with judicious ratholing, you can show up as a big ol' losing ploppy on the pit computer. Hell, I get a big, friendly, "welcome back Mr. XXXX" and ZERO heat whenever I play locally, and I don't generate too much heat elsewhere (aside from downtown Vegas) despite wide spreads. Again, these skills come with time and practice.
You also commented about the difficulties in wonging into tables. This also takes some practice. Ploppies observe games all the time to see if the dealer is "hot". Others watch for entertainment. Just convince yourself of the reason for observing, and act accordingly (don't act suspiciously). Also, games can be watched from the slots or from the craps tables. You should be able to wong into ANY game without a "no mid-shoe entry" sign. Screw the ploppies if they complain. Again, practice makes perfect.
In closing, stick with it -- the wins will come with time.