Just started taking speed

I have recently started experimenting with speed. I have been taking low doses at work and the effects have been enough for me to continue to use it. I sprinkle a little in my water before work and again around 12pm.

I’m worried about brain damage and becoming addicted to this substance. I have little to no experience with amphetamines before and I’m afraid I’m blind to the negative aspects of the drugs.

I was hoping someone could share some experience/reasons that I should quit now. It would be very appreciated.