“You can recover “ordinary” lost FP by resting quietly. Reading, talking, and thinking are all right; walking around, or anything more strenuous, is not. Lost FP return at the rate of 1 FP per 10 minutes of rest [=3 FP per 2 Tasks]. The GM may allow you to regain one extra FP if you eat a decent meal while resting.
Certain drugs, magic potions, etc. can restore missing FP, as can spells such as Lend Energy and Recover Energy.”
So, good luck finding a Wizard to help you with that…
See Missed Sleep for rules on recovering FP due to Missed Sleep, which are different to ‘regular’ loss of FP.