120g is the minimum carbohydrate you should be looking at. Any less than that and your body will start entering ketosis.

Low carbohydrate isn't always the best advice for people with reactive hypoglycemia. At least I assume it's reactive hypoglycemia you've been diagnosed with? Your doctor should have given you at least a brief dietary outline for you to follow, which would have sounded something like "eat small regular meals, include fibre with each meal, and avoid sugar". 'Sugar' is what will cause a hypoglycemic attack, not complex carbohydrates.

My advice with regards to your carbohydrate intake would be to increase it until you're more comfortable. Get your carbs from veggies and good wholegrain sources. Don't be afraid of the finer details and what monstrous carbs could possibly be lurking in your food like ninja's, this will come in time. The most important thing is to cut out sugar and processed foods so you can avoid the blood sugar drops.

My advice with regards to fat, you can increase that quite a bit more. A lot of men on low carb diets (some as low as 20g!) will increase fat massively. As long as your fats are coming from 'good' sources (not saturated fat) then that will be fine.

For me, I used to be on a 20g carb, 150g protein, and 92g fat. This amount of fat was too high and with the carbs being so low I found my body in ketosis, not nice. I'm now on 120g carbs, 120g protein, and 62g fat which is a much better balance for me.

For you, you'd need increase all three of those values according to your total calorie intake which will obviously be higher than mine. What you detailed above is only 2000 calories, which seems quite low for a well built but underweight male (and is probably why you're hungry!). You might want to reconsider your total calorie intake. 2500 may be better, depending on your activity level you could be look at higher again.

You could try 180g carb, 180g protein, and 110g fat. I know the fat seems high at first, but get this from healthy fat sources and you should find you're fine.

Don't worry about consuming excess protein. Excess is 'converted' to glucose through a process called glyconeogenesis. This glucose synthesised by the body can be used (to an extent) in the absence of a higher carbohydrate diet. It's more complicated than that, but still, don't be afraid of a little excess protein

As for what to eat for hunger, some good ideas include peanut butter (if you like this, stock up!), cheese (but not 'too' much cheese), eggs, milk and shakes (possibly protein shakes if you want to go down that route), complex carbohydrates...There's plenty of lower carb recipes on Google as well as snack ideas and tips. Preparation is the key here.

If you're really into the more scientific side of your diet let me know and I can point you in some directions.