If you suspect you might have a food allergy based on some of things mentioned, you should consider an Elimination Diet. Basically what an Elimination Diet is meant to do is remove the common food allergy-triggering foods from your diet for a prolonged period of time, allowing the body to purge itself and clean out all the antibodies that are sending your body into defense, inflammation mode.
Depending on the severity and length of an untreated food allergy you will need to remove all 5 of the common allergy foods for a minimum of 21 days, although I highly recommend upwards of 3 months. I know that might seem a bit excessive, but you have to ask yourself, are you tired of living in a constant state of feeling like crap? If you answer is yes, really, what is 3 months in the big scheme of a healthy, happier, better feeling you, for the rest of your life?
After the 3 month Elimination Diet, you introduce the least offensive food to you, first, one time only and wait a week. See what happens. See how your body responds. See how it makes you feel. If you feel nothing, move onto the next item on the list. Again one item, eating it only one time, with a week in between items. Leave the most offensive food as your last to re-introduce, often gluten and dairy. If your instinct is telling you, or you are having a very strong negative feeling to adding those foods back into your diet, DON'T, your body is telling you they are not your friends.
At that point your Elimination Diet is over. Eat only the foods you know you don't have an adverse reaction to. You can always come back to an Elimination Diet if you find yourself veering off course or by mistake you ingested a trigger food.