Gastrointestinal problem. Serious?

Hello doctor, I'm 23 Yr old female and I'm suffering from excessive bloating and gas from last 1 Yr. At first my symptoms include constipation but not I'm having alternate diarrhea and constipation. I'm seeing lots of mucus in my stool. Also my stool is very mushy, I don't know if this is normal. Sometimes I also see blood or pus something with mucus. I also feel very weak and have joint pains, dizziness,heartburn, nausea. I feel mild pain in my right side below belly button. It is reoccurring. Like when I stretch my body or when I bent down. I feel like something is wrong there. I had my endoscopy and it was all clear with only inflammation in my stomach. I don't know what is wrong with me. It's making me depressed. I feel weak all the time. My joints hurt. Is this something serious? Please guide me what to do next.