1990 Honda Civic Clutch and Bell Housing

Yeah, I have a 90 Honda civic. Not sure what motor it is, but I think it's a d15. It has a carburater. Looking on the motor, it says ZC too. It's a 2HG hatchback.

Just bought the car and drove it to work back and forth and then at one stop light it started to get harder and harder to shift. It got too hard and won't even shift. Had to struggle for it to shift. Got to my house my house and turned it off. I tried to find a place for like a clutch cylinder to put clutch fluid in and couldn't find one. Looked under the car and found out that I could see the flywheel in my transmission. I think there isn't a trans housing or I think it's called the bell housing. I don't know for hondas but I'm sure all transmission suppose to have a bell housing. I decided to just spray the flywheel with wd40 and it shifted good for a drive down the street, but got stuck again.

I would like to know if I could just put some grease on the flywheel or go to a junk yard for a bell housing? And are all the D15 or 16 bell housing the same? What should I do? The clutch is stuck.