Did you ingest 65mg TOTAL in the past 3 days or 65 mg per day for the last 3 days? I'm assuming you meant 65 total, and if that is the case, 50 mg will likely be a pretty decent sized dose for you, because if you have taken 65 in last 3 days, thats only ~20 mg / day. Tolerance does not build that fast. So if the 20 mg or however much you took in the last 3 days got you buzzed, you will probably be pretty high from 50, or at least feeling very good.