IMHO, your comfort with a gun is more important than size. A .38 is a great size and does have the stopping power for most situations. If you are comfortable with that, stick with it.
a .380 in hand that you are comfortable shooting when the SHTF is better than an ak-47 at home in the closet. Practice and situational awareness is the key to surviving.
Get hits.
Get lots of hits.
I just had the occasion to shoot what the guys called my "Europellet gun" (Glock 17) with two guys shooting .45ACP compact pistols in a tactical exercise under stress.
I got lots of hits. Lots more hits than the .45ACP guys.
In a gunfight, hits are the thing. If two hits don't work, get more.