Cat walks weird and poop always leaks - Help

Hello! I'm quite new here and this is my first post. As you may have gathered from the title, this post is going to contain some gross stuff.

I'm here to ask about my 11 month old cat. She's been walking weird for the past few days. It mostly looks like her hind legs are weak but she still has enough strength to jump upon furniture... though sometimes she fails to really get a good grip and she falls. At first she was just sort of limping slightly, and sort of slightly dragging her right hind leg a bit, but now she looks like her hind part is  bit... uh, dizzy?... She also walks around a lot trying to look for food (which is normal behavior for her - she likes to eat a lot). And she's also been leaking poop. At first, it was just a really small amount so we thought she was just being lazy and didn't clean herself up well, but now, there's usually a small amount about the size of a green pea and her butt is bulging a little. This morning, there was a spot of blood there when I wiped her but now there's no blood anymore - just that one spot of blood. She still seems really energetic though. Her appetite remained the same if not increased and she drinks a lot of water too. She pooped once on the floor and her poop looked thick-creamy. I asked my brother if I should take her to the vet but he said it was probably diarrhea or blockage (because sometimes we catch her chewing on stuff like string and small food wrappers she takes from the bins). He thinks since she's energetic, it's not something serious and a trip to the vet would not be necessary. What do you guys think though? Do these symptoms look like diarrhea or blockage to you?

It sounds like she does really need to go to the vet.  At the very least, she must be incredibly uncomfortable.  I would get her in as soon as possible.

It is not normal for an 11 month old cat to be leaking poop. Is she peeing at all?   If she is not peeing at all then maybe there is a blockage.  At the very least your cat is probably very uncomfortable. I agree with talkingpeanut that she really does need to see a vet as soon as possible.

I am not trying to scare you but if you have any reason to suspect any type of blockage then it needs to be dealt with quickly.  I lost a cat to a blockage years ago because I did not catch it in time.  Hubby and I were very busy with work at the time and failed to notice one of our cats was not going to the bathroom.  We did not realize something was wrong until hubby went to pick her up one night and noticed she had lost weight.  He tried to feed her wet food and she would not eat it.  We rushed her to the vet the next day. The vet thought she would be able to save Baby-T but it did not work out that way.  There was a lot I did not know back then and I do not want to see anyone else go through this. This was over 10 years ago and it was a big learning experience for me.  Blockages are fixable if they are caught and treated right away.  One of my friend's has a cat that was recently treated for a blockage and is now completely healthy because she caught it quickly.