I haven't had a problem finding .380 ammo. Cabelas has a decent amount everytime I go. But I agree with the .38 snub suggestion. A S&W642 would be a nice pocket gun. Although if you would want you could get a .357 snub so you can shoot .38 also.
The downside to the .357/.38 idea, from my point of view..
The standard .357 steel revolvers are hefty. Pocket carry just isn't a good idea for lots of folks.
The ultra-light .357 revolvers from S&W are SPENDY! And full-house loads from them are painful, trust me, I've tried..
My deeper-cover handgun is a S&W 438 revolver. I carry .38 +p rounds in it. Works like a champ, more accurate than I am, and it hides in a pocket like nobody's business.
Op, you said you want a pocket gun. As nice as the CW9 and snubbie revolvers are, they're really pushing the envelope of what it means to be a "pocket gun." I do not view them as such. As an example, I had a CW9 with me on a vacation recently. Threw in a few holsters as I am wont to do. The CW9 could not be carried in its pocket holster (Desantis Nemesis) in ANY of the pants I had packed including 3 pairs of typical jeans, a pair of cargo pants, and a pair of dress pants, ergo not a pocket pistol. It can be pocketed if you pick your pants carefully, or in a coat pocket, but don't count on it in pants if the pockets aren't particularly large (same thing for 642s, LCRs, etc.). I have carried both in a pocket on occasion, but they're not as likely to fit in this role as as the tinier semiautos and mini revolvers (like the NAA).