If I'm doing something of low to moderate intensity (swimming, walking, jogging) I expect my levels to steadily drop, so I would drop my basal to about 50% for about an hour beforehand then I don't wear my pump at all while exercising.
If I'm doing something fast or intense (for me weightlifting, spin class, sprint session) I tend to spike up then crash down later, so I'll bolus about an hour or two before to avoid the initial spike, then drop my base rate as previously.
Hope things start to get easier for you; I'm dealing with a lot of fluctuations at the moment so I know how awful it can feel. But there will be a solution out there! R x