Oke well I don't know how C# exactly works I can read the code but I don't know the details but i'll try to help you.
This is how I should create this tool:
Well uuhm idk how exactly memory reading works but I suppose that your way works
Uuhm well I should create some kind of timer which checks the sp like every 5 seconds(you could also create a trigger but an timer is easier I guess).
well like you already did you got an starting sp and the current sp so the way you're doing it might work but you need to have some timer which updates the sp every 5 seconds and also updates the labels on your form. Idk if this is the whole code cause you're not using any of the "timer" functions but I guess that's just cause you were testing stuff