Just a Test: Can I Play NLHE?

Second in line in the Bellagio buffet for breakfast (opened at 8:00, which I wasn't aware of). I got the first omelette (bacon, ham, jalapenos, and cheese), and then had bacon, eggs, and steak for my lunch for today (double dip). My package I'm expecting hadn't arrived yet, so I headed to the Poker Room. Totally empty, so I asked what they had (one $15/30 table, a few $4/8 tables, a couple $2/5 NLHE $200 max buy-in), so I decided hey, let's test this theory that I can't really play cash NLHE. I bought in, to my left was an aggressive guy with $700 in front of my, pushing folks around with rags. To my right was a 24 year old with $3600 in front of him. I fold/fold/fold for awhile and catch 99. My neighbor on my left raises to $40 after my limp, Asian young guy goes all-in for his $200, I push as well, and the guy on my left calls with AQ. Asian guy has TT, but the 9 on the flop and no eight hitting pushes the main pot to me. I bleed off a couple of hundred, once not pushing with 99 again when my neighbor had raised and an all-in junkie who had rebought four times in less than an hour pushed. That guy had A9, and my neighbor caught a straight. I had a new tight 40-year old guy raise to $40 with three limpers, so I jammed with $250 holding AKo. He took awhile to fold his QQ, which held up. I rebought, nothing going on for awhile. A fairly tight guy to the left of my neighbor called my raise with AJo. I had just gotten a call from my office, flop came J high with two hearts, and I checked it for some stupid reason. Kh comes on the turn, I bet and am called the $50. I then shove all-in with a rag on the river (he has AhK) and I get up and leave.

So I quickly give back a chunk of my win yesterday. Should I have just split with my triple up, thankful for the $375 win? I'm just not good enough in the cash game, not good enough to prevent donking off $100 at a time. Sitting and praying for monsters is just no way to play, so if I've got time to kill, I think I'll have to play low-limit. Maybe the lower NLHE than even this where there are heavy neophytes, but when you're outchipped like this, it's primarily a shove fest to get any chips. I totally misplayed the last hand and should have been able to push and at least keep going, but it was another example that I can play tourneys but not cash NLHE. Is that OK? Is it an indictment? If my AK doubles me through, am I suddenly better? I think it's more of a fact than anything that I'm just not strong. I tend to bleed off chips when I'm up and play fairly scared most of the time, which is easily exploited.