1. What are you eating? If you're on a high-carb diet with relatively high postprandial BG levels, what's called glucotoxicity will gradually destroy your beta cells, and your diabetes will get worse. If this is the problem, you should try cutting back on your carb intake.
2. Have you had a GAD antibody test? It's possible you're not type 2 after all, but LADA, or "latent autoimmune diabetes of adults." If this is the case, no amount of oral medications will help, and you should just try insulin. Ask your doctor about the test.
If you're thin, LADA is more likely than if you're very overweight.
Another test is the C-peptide test, which indicates how much insulin you're producing. Type 2s usually produce a lot. If the C-peptide is low, it's another indication of LADA.