Oof yes I get this on 5:2 too, although with me weirdly it's usually in the morning on the day after a fast day, rather than on the fast day itself, not sure what that's about?
My solutions are:
-The big one is to keep hydrated as I think the headache/dizziness/nausea some people experience when fasting is 90% dehydration rather than genuine hunger pangs (providing you are eating enough when you do eat). So lots of water, herbal tea, black coffee, even diet soft drinks or squash as a last resort - all 'allowed' and don't count as breaking a fast. By the time the 'feeling' sets in it's too late, so I need to remember to drink at regular intervals, more so than I would if not fasting as you do take in a lot of fluid through food. Maybe try setting an alarm on your phone to remind you to drink if you find yourself forgetting? I quite like really well chilled/iced sparkling water, sometimes jazzed up with lemon/lime slices - something about the 'texture' makes it more 'filling' somehow than regular water? 
-A spoonful of soy sauce or marmite on a teaspoon, just on its own, gulped down like medicine. I think in theory this replaces salts and minerals which can be lost if not eating food, it seems to help me although this may be purely psychosomatic.
-Along similar lines, chewing some gum can also help me, I think possibly (?) the chewing motion sets off some 'eating' hormones, or again maybe it's just imaginary. I know it's a disgusting habit but luckily in lockdown no-one can see/hear me.
-As you are doing 16:8 and if you are regularly getting this right before you break the fast, would it be possible to shift your eating window a bit? So if you currently eat 1pm-9pm but you regularly feel starving at 12.30, could you shift to 12.30-8.30pm?