What is the effective treatment for digestive problems along with heavy bloating in a 23-year-old?

Hi doctor,

I am a 23-year-old male, currently weighing 119 pounds. A year ago, I weighed 132 pounds. I have been experiencing digestion problems for the past 5 years. Over the past 6 months, my symptoms have included mostly constipation, but I have also had episodes of diarrhea in between. A couple of months ago, I was diagnosed with colitis. I had loose motions five times in a row within a few hours, and after an ultrasound, it was determined that I had colitis. Now, I am facing heavy bloating, occasional breathlessness, and there are two to three days between passing stools. Additionally, my stools have black spots or sometimes contain white undigested parts. Over the past couple of days, I have had bowel movements six times. I have been taking VSL probiotics, ornida antibiotics, and rabium for the past 5 days. I would appreciate your guidance. While there is no intense pain, I feel a sense of heaviness, fatigue, and sometimes experience slight chills.