I am over 31 or so and had a bunch of relationships. One way to see it that if feelings are involved, like it seems you have feelings for her, it is time to stop play games. THIS IS NOT PUA ANYMORE! If you had sex and are clearly interested in her it is time to stop PUA stuff and act more like an AFC again. If you want sex without feelings at all, continue with PUA stuff.
The natural thing to do after sex, if feelings are involved, is to express the feelings and talk romantic sutff (like what you did). The problem with that is that one can get hurt, and also you are more vulurnable as you open up, but it is worth it.
Now she said: "she would send me pictures". Do you get that? So I remember like 3 girls that said that to me, when they went away. All three times the girls had feelings for me. This is a good sign, especially if it is a hot picture or like in bikini, or so.
Definitely call her when she is back.
I see it this way: in this situation, where it makes the impression that feelings are involved, act natural. Express what you feel is in many situations a lot better than playing games. You are congruent. If she doesn't like you you find out early. Playing games might slightly improve your odds, but also greatly increase the odds that you fuck up.
In Germany we say good luck
