Starting Medication: No Life-Changing Effects?

Yes my doctor said it has to build up in your system which is fine. What are doses for then ? Like does it take all doses to adjust to your system or does it take 2 weeks for the right one. It's kinda confusing but you get what I'm saying ?

If you take Tylenol or allergy medicine you usually feel it right away right? I mean you have to you feel aweful so you need it to help you like now or maybe in like 10 min . Well I mean how do you know for the next week or 2 you still feel nothing like you might be on the wrong dose. I'm just really not good at waiting around for a medicine to start working. When all other medications I took before this one gave me some sort of feeling right away. They were bad affects but least it was something so I could move on to the next medication. Like yah it's like I just wanna get through the medication and find the right one already not just wait around .