Vejables I have felt the same when I try to use the bathroom. A lo of times I think I have to pee but barely anything comes out. My mum says it's the pressure of the baby on my bladder that makes it feel that way so I think it's a normal experience in 3rd tri. Plus your bladder fills up super quick being that it's slightly squished and has less room to hold onto stuff.
As for the itching, I think I remember a few other ladies on the forum saying the same thing, and it was due to stretching. Try rubbing a bit of olive oil or lotion on your skin nights maybe?
And I'm very sure you didn't squish your lil one. I have this pregnancy book that says it's common to feel a lil weird down their after sex because of the mild uterus contractions during orgasm or something along those lines. They said mild cramping is normal too and only to worry if you experienced a mucusy discharge with heavy bleeding or something. But more power to you and hubby for having a lil fun

It's quite possible your tummy looked different because your lil one moved too during the activities into a new spot.
Try not to worry, hope you are feeling a bit calmer. And I'm jealous that your date is ahead of mine now hehehe
P.S. Ok I just read back and read the other's comments LMAO@ Madwolf's comment "Not pleased with the intrusion"..LOL too cute