What other meds can I take for diabetes type 2 besides going on insulin?

I have tried Actos & Avandia in the past (retained water like crazy). I have also tried Metformin (my stomach cannot handle even 500mg). I have been taking only Januvia for a month, but it is not helping to control it enough. I eat a fairly good diabetic diet and walk every day. Should I get stricter still with my diet & exercise even more?