Hello,
I began drinking wine tonight and after my second glass was feeling very drunk and not in control as I normally have on naltexone, so in my haze I decided to take another half a pill. so i've had 75ml tonight. Was this a stupid thing to do?

It's not a problem. Search this site for "100mg". You will see many TSMers who have gone to 75mg to 100mg dose and saw results. I did not read through them all but there are plenty there to investigate for yourself. (use the search magnifying glass next to the "?FAQ" button above.

Not a problem to up the dose, though you should not use it to cure your drunk feeling, but your cravings. You WILL feel drunker, faster, on nal (in my experience). Hopefully that is a deterrent. Upping your dose should only be done if you feel you are losing control.