Ativan dosage

I have ativan. 10 pills at 0.5mg each. I'm solely taking these for flying, I don't take them regularly.

I've taken them for flights before and once they helped, one time it really didnt stop my panic. I took two over a 5 hour flight and no help. The time I used them before that, i had instant calm and relief.

I really didnt pay attention to the dosage though for either of those times. Do you think the dose I have right now is enough? 0.5 mg for a sublingual (under the tongue) pill? I am a very tall girl 5 foot 9 and about 240 pounds. So I usually need a higher dose of stuff anyways just cause im bigger. On my prescription for the current bottle I have now it said "warning: this dosage is lower than reccomended by pharmacists". like what? does that mean I should maybe take two at a time to avoid panic?

How much is an overdose? liike how many mg? I really want to be calm while flying but I dont want to hurt myself either. I am anxious already not knowing what to do.