The next paragraph is a background of my situation. Longwinded and boring yes, so if you want ski pdown to the question under it.

I was started on 5 mg of adderall (XR), and it worked wonders. Id say about a week or so after, i increased my dosage to 10mg (it was perscribed). That worked well, i had a clear mind throughout the school day and everything went well. After about a month and a half, i realized that i did not feel as focused as i did when on the medicine right after the dosage increase, but i still felt very concentrated. When i got perscribed 10mg capsules, i still had a good amount of the 5 mg ones left over. After a couple weeks i started myself on 15 mg of the adderall since the effects of the 10mg started fading, and all was well. Now, id say about a month later i felt the 15mg effects decreasing, so i began taking 2 10mg capsules, and up until now they work great.

My question is, will my body keep getting used to the drugs like this, or will it stop at some point? Am i overreacting when i no longer feel very clearheaded, when i sometimes feel myself daydreaming?

That is a good question! I've been wondering that myself! I've pretty much had the same experience except my dr. increased the amount. I asked her if it was possible to become "immune" to the current amount and need to increase it and she said no... but then again, she is the same dr. that told me adderall would last for 24 hrs....

boy that's a bad doctor.

When you first start taking it, your doctor will often start you at a low dose and work you up to the dosage that you find works the best. 10 mg is not a lot of Adderall although it is enough for some people. Is it Adderall XR that you are taking?
Some people do develope a tolerance for stimulants, but this is the exception rather than the rule. What you likely notice now is that the "buzz" is diminishing, which is normal. As far as the positive effects of the drug on focus, etc. - they don't diminish, usually. What I'll bet is happening for you is that you aren't at the optimal dose yet, so you feel the initial benefits when you first take the pill and the effects are at their peak, but as the level of the drug in your bloodstream drops below a certain point, the effects go away.
People have taken stimulants for years and they don't have to increase the dose. Your brain does get used to some effects of the drug - in particular the increases in HR and BP - but studies show that the improvements to focus and impulse control don't go away.