There is an issue here in that you have both and blood and weight loss. Mucous is pretty normal in IBsers and is harmless.
But because you have both issues and two "red flags" for IBS, blood and weight loss. I would see a doctor about it.
I am not a doctor. All information I present is for educational purposes only and should not be subsituted for the advise of a qualified health care provider.
Please make sure you have your symptoms diagnosed by a medical practitioner or a doctor.