Allergic reaction?

Idk whats going I have never in my 23 years of living had this happen or any type of allergic reaction , it itches & burn at times, it has spread to my face & lips , & also has been happening for 2 days in a row first day I went to ER & all they did gave me Benadryl , it took it down yesterday night was the second time it happen , & im currently on my first trimester.