Uncomfortable feeling like everything is falling out of me and a constant pressure that is pushing my vagina open. sex not the same for me or partner?

Prolapse: Sounds like uterine prolapse. You should see your gyn for an exam. There are non-surgical and surgical fixes for this.

Infection: Sometimes this sensation occurs because a woman has an infection. Could be as simple as a yeast infection. Sometimes could be bacterial infection. Rarely a syndrome like vulvodynia or a chronic pain syndrome in the vagina. Definitely see a gynecologist and get checked out to make sure nothing serious.