Dependance on stims can develop over long periods, tone it back slowly. They increase BP and your body is used to moderating this by decreasing it. My BP is much lower and still going through medical testing to fix it.
If pre workouts are dosed heavily you should tone it down as well, vasodilators like agmatine, nitrates, etc. will lower BP.
Also drink more, a lot more, regardless of how much you drink now. Hydration is key to keep up BP especially when heavily using stimulants which will be pushing fluids out.
Chug a litre of water and retake BP, for me the increase is quite noticeable.
Sodium intake will help as well, add some sauces into meals for an easy fix, snack on pickles, or of course just more salt.