I am 37 year old, all my life been eaten same things nothig unusual, a week a go i had a severe food allergy to nuts and pecans, i wonder why now?

It can happen: Food allergy can develop during adulthood. The most common foods that cause allergies to develop during adulthood include nuts and shellfish. I recommend that you carry an epi-pen and know how to use it in case you eat nuts by accident.

Epi Pen: Adult onset food allergic reactions may occur. As reported in an article by Joyce et al; 'The relative frequencies of reactions (systemic or localized) to specific tree nuts were reported as follows: walnut, 34%; cashew, 20%; almond, 15%; pecan, 9%; pistachio, 7%; and hazelnut, Brazil nut, macadamia nut, and hickory nut each were less than 5%.' I would suggest testing and avoiding all nuts.