You may want to consider the possibility of celiac issues. Extreme fatigue can be found in many with that issue, although unfortunately many GI dysfunctions and other medical problems can also result in fatigue.
Go see a doc.
You've probably got a gastric bacteria in your guts, it can cause gas, and also since it's a bacteria, your natural body resistance is fighting it, so that can make you very tired. You'll need to go to the doctor and they will do a stool sample and maybe draw some blood, to see what you've got that's doing this gas thing. They should be able to give you some medicine to kill the bacteria, and this whole episode with the gas and tiredness will stop.
It's also possible you have ordinary food poisoning, in which case you ALSO need to see the doc, again he'll give you medicine for it. If you do not eat breakfast or don't like it, could be by eating a little in the morning, the gas will release before you go to work, which would be a BIG help. Or you can just quit eating lunch until you get better after seeing a doc, and that way the gas won't come out until you get home and eat supper. Quit trying to exercise or doing anything radical while you're sick, or else you might indeed pass out. Your body is fighting infection and is absolutely exhausted, so just rest. But you MUST go see a doctor, this is not going to go away on its own.