I used to work for a gastroenterologist (affectionately called by those who worked there, the "p**p doc"). There are some questions a receptionist or nurse would ask you about the bleeding...so I will ask them and maybe it will help you decide how much of an emergency this is. First, what does the blood look like? Is it dark brown? Does it look like coffee grounds? Is it bright red? How much is there? Does it turn the toilet water bright red? Or does it tinge it pink? Is there bright red on the paper? How much? Pinpoint spots or more then that? Is there blood at other times? Do you find blood in your undies? Where EXACTLY is the pain? Is there pain after you are finished? For how long? Is there any itching?

Now te explanation...coffee ground looking blood is probably coming from the extreme upper GI tract (stomach usually), this is an emergency. Dark brown blood is also upper GI tract, but lower than stomach and is also an emergency. Bright red blood that turns the toilet water dark red, and/or leaves lots of blood on the tissue, and/or is there at other times, is lower GI tract, but still an emergency. Pink tinged water, pinpoint or small smears or even one medium sized spot on tissue, itching, pain specifically at the rectal opening that lessens after but is still uncomfortable later, is usually due to hemroids and/or irritation...the irritation could be due to IBS or the other thing you mentioned...or both together. This is not an emergency, but should be checked out soon, to make sure that is the problem, and also to get treatment if needed. A GI doc can cauterize bleeding hemroids, or remove them (surgically). This type of bleeding is very common with IBS.

As for the leg...get it checked ASAP. It is possible you have an infection, or some other problem going on. There are signs that indicate an infection, butthe leg is a large limb, and the signs may be deep under the skin, so not visible, but still there.