albendazone taken alone is recommended by ICU for only the treatment of roundworms. If you have another type of parasite, ICU's other protocols call for at least two different Rx drugs together for synergistic action (according to ICU's protocol).
Have you done a stool test to see what parasite you might have? i know the stool tests are often inaccurate abut at least it could give us some clues.
My guess is that since you are no longer constipated, the albendazone did kill the roundworms, or at least greatly reduced their population size. However, you probably have/had more than just roundworms.
And did you get your drugs from a doctor or from online?