Just so frustrated

I've had type 1 diabetes for about 20 years now and it's still so unpredictable. My sugar went super low before sleeping so I ate a bunch, then it went super high in the middle of the night so I corrected and then dropped way low again in the morning and I ate a carb heavy breakfast, took less insulin so I could get a work out in. My blood sugar started going a little up so I decided to head over to the gym. I get onto a machine and notice my blood sugar going low again. I'm now in the locker room trying not to cry but crying a lot. So frustrated.