I don't know if two weeks is enough to set up a tolerance or not.

I do know that when I took my first tablet, of 50mg, I hallucinated all night, and didn't sleep at all.

Then I used 25mg a night here and there, for about 7 doses. I then bumped up to 50mg and no more weird mental effects. But sometimes it does interfere with my sleep. But the next day I feel so much better...it is like it lasts the whole next day for me too. I don't even take it once a week. But I have found bursts of 3 days in a row very good for major pain issues. (mostly arthritis, and some foot burning). It works really well for the burning. Less well for deep intense pain. And it worked pretty well when I had my root canal last year.