I Am Having A Severe Allergic Reaction To Poison Ivy

I am having a severe allergic reaction to poison ivy right now. My eyelids ,cheeks, nose, and hands are all swollen substantially. I took 5mg of levocetirizine. I am a 56 yr old male in good condition, non smoker. No other health issues except allergies to enviroment. Dust, pollen mold, ragweed,etc.
Can i take another 5mg of levocetirizine without worry? I weigh 140lbs.