What Causes Severe Constipation Along With Mucus Plug In Stools?

Hello, I am a 26 year old relatively healthy male. Im 5'10" and 144 pounds. I recently (about a week ago) was having constipation, a day later I had diarrhea. From then on I had mucus in my stool for about three days before going to urgent care where they prescribed me Cipro. The Cipro made me feel terrible so I only took the first dose(the side effects scared the hell out of me). The day after I took the Cipro I had fecal impaction which I had to use and Enema to relieve. I went for two days without the Cipro, taking only a wheat/dairy free diet with lots of water, probiotics, and rest, with 100mg of Colace each day to soften the stools. I called the doctor back on the third day and am now taking metronidazole. My stool is still pretty hard (im only on my second doseof the metronidazole and stool is a hard clay consistancy) and today I felt almost a cramping pain (sharp) in my side (abdominal area near colon) after finishing my bowel movement but other than that the mucus is not visibly present in the stool. No blood or anything like that. My main concern is the fecal impaction and whether or not my stool will begin to soften without colace. I have been drinking a lot of water(and always have) and have a close to whole foods diet with the occasional splurge(especially over the holidays). The fecal impaction was a pretty terrible thing and I wish I knew what was causing the hard stool, or if its related to the mucus in the stool that was occuring. I have no health insurance and am unemployed and I'm beginning to worry that there may be a more severe underlying condition. Thanks, any comments are appreciated.