There are some common causes of such bleeding from the urethra. The common ones are UTI, trauma, kidney stone, bladder stone, acute nephritis, Prostatitis, Prostate cancer, etc.
As per the symptoms you have described there is a likely possibility of some urinary tract infection which is causing such symptoms in you. The kidney stone can also cause such symptoms of abdomen pain, Haematuria, etc.
I advise you to have the relevant investigations done like abdomen Sonography, x-ray kub region, urine routine examination, blood counts, etc. after consulting your urologist.
The treatment depends on the underlying cause. The antibiotics like Norfloxacin, Septran, Metroidazole may be prescribed for 7 days to control the bacterial infection if present. The treatment of other causes is accordingly.