I have recurrent constipation with bloating and gas formation. Are these signs of IBS?

Hello doctor,

I have been facing stomach issues like constipation for the past several years, for which I have been taking Isabgol for the past decade. For the last four to five years, the constipation was increased, for which I have shown the physician who, after doing a physical examination, said that I have been facing the problem of IBS. He put me on medication for 15 days. Lesuride 25 mg thrice a day and Superia once a day and asked me to take Pegmore instead of Isabgol regularly. This worked well for five to six months. Then, I faced a similar problem again. I again went to the same doctor who suggested taking Ganaton 50 mg forever and asked me to take Pegclear instead of Pegmove. It worked well for some time, maybe for two to three months, but I still faced similar issues like stomach fullness, bloating, constipation.

Subsequently, I showed to a gastroenterologist who prescribed me Cizaspax twice a day, Ganaton total once a day, and Pegred before going to bed. Initially, he prescribed me these medicines for 15 days and later asked me to take them lifelong. These medicines were prescribed to me for the last one and a half years. I have been taking all these medicines on and off but not regularly. But I still feel the stomach fullness, bloating, and hanging sensation in the pelvic zone, which makes me feel like I am carrying a huge weight around my waist area. Even when I sit, it makes me feel that I am sitting on a tube full of air, and while standing for 5 to 10 minutes, I face difficulties. Please advise. My MRI perineum report was normal.