Help! Weird symptoms that have nothing in common.

Hello all.  I am new here, but when I was researching my cat's symptoms, this site kept popping up.  You all seem very knowledgeable and helpful, so here goes.  I came home yesterday to a cat that was not quite limping, but taking a shortened stride on the hind end.  I couldn't really tell which leg it was.  I can find nothing wrong with his legs, pelvis, feet, etc.  He did jump up onto the counter for food.  He ate normally.  Last night he pooped on my bathroom floor and in the bathtub which is weird.  This morning (Saturday), the limp was worse so I called the vet.  They had no openings for today, but can see him Monday.  This afternoon, the limping is worse, he had to strain to get up on the couch and is mostly lying around behind it.  He doesn't seem to want to move and has pooped in the bathroom again.  I was petting him earlier and when I put him down, he yowled at me.  So, the question is: 1) What does this sound like?  2) Can it wait until Monday or should I call the emergency vet? 3) Can I give him anything for the pain?  I know that tylenol and advil are out so please don't yell at me.

Thanks!

How old is your cat? What's his medical history? Any known problems? Is he dragging his legs behind him? Is he drinking? Has he peed?

To be honest, I'd be pretty concerned if this was my cat, especially since it continues to worsen. It really could be so many things, ranging anywhere from a sprain to complications with an internal organ.

There are no over-the-counter pain medications safe for cats. Only a vet can prescribe something.

I agree, what caught my attention is how it's progressed.

Pooping in the tub is also a clear sign of something not right.

He does need a vet asap. I would find it very hard/impossible to hold out until Monday.

Try an alternate vet.

I also wouldn't assume the 2 have nothing in common.

Take for instance if he has one of his organs inflammed and causing pain, he would walk differently.

The pain would cause him to poop in the tub too. Their way of talking.

He is a four year old domestic short hair.  He was attacked as a kitten and has a bum back left leg.  It doesn't cause him any pain or limp, but he is missing a claw.  He is not dragging his legs at all.  It's a short, hop step on the back end.  He also isn't pushing off it as hard as off the other side.  I have localized it to the back left leg.  He peed this morning, but has only pooped since then.  I haven't seen him drink yet.  He is eating just fine.

And before I forget, thank you for the helpful replies. 

I certainly can't diagnose him; but, the first thing that came to mind is constipation. It could explain the short-stride walk and the poop accidents.

Also agree that, if this were my cat, I wouldn't wait until Monday, especially since things are progressing.