Lantus and medicine

I have just started taking Lantus Solostar. I'm usually not allergic to medications, but this time I have developed diarrhea. The condition worsens soon after my meals, there is some amount of cramping throughout the day. Imodium helps, but only on the days I take it. The only way to avoid diarrhea is to skip doses of insulin or to have Imodium everyday.

My doctor added Lantus to my medicine regimen including Byetta 10, Metformin 1500 twice a day. On the Byetta I lost 35-40 lbs very easily. The moment I added the Lantus I was bloated and over a 2 months I had gained back all the weight I had just lost. When I asked my Doctor about the bloating and weight gain she said she didn't think it had anything to do with the Lantus. But I was losing weight until she added the Lantus! I don't think that's just a coincidence. What should I do? Should I go to a doctor who specializes in diabetes instead of my family doctor who I love dearly?

Has anyone taking Lantus had a ringing in the ears and a slowing down of their bowel movements because I have since taking it.