First run a piece of paper at the bottom of door to identify where is sticky.
Interior door suddenly now scraping floor.
Use a pencil or a label to mark where you need to sand down.
It sounds like perhaps the door frame is leaning in towards the bathroom or perhaps the bathroom floor slopes up a bit.
Houses settle over time which often causes a door to sag inside its frame.
A dragging corner makes a door difficult to open and close.
Use sandpaper a belt sander or circular saw to remove the area where the door rubs.
The dragging door corner can scrape the floor or threshold.
Sandpaper can be used for small rubbing problems while the belt sander or circular saw are ideal for more extreme door sticking issues.
Be careful not to cut the door too deep or too far.
First check that everything is square.
Adjust the top hinge 1 use a screwdriver to tighten the screws in the top hinge on the door and frame.
Can you tell which it is.