It's so overwhelming, I (WE) know! When all is not as you think it's SUPPOSED to be, it's easy to simply give up, isn't it? Story of my diabetes life. I recently switched to a new endo who changed my whole outlook. In the past, the docs always made me feel like a bad diabetic for not being in perfect control. My new team let me know there is no such thing as a bad diabetic, only a diabetic who hasn't found the right routine to fit his or her lifestyle. So I've stopped trying to achieve "perfection."
Take it one day, one blood sugar at a time, and try not to beat yourself up over it. I've found that making more realistic goals for myself works.....not every BG will be a 100.
Really, it's not possible to fail; it's a matter of being consistent at working at it and accepting that no one is perfect (I'm talking to myself here). Give yourself some wiggle room to be human and hang in there!