Possibly developed a new allergy

Hi there, yesterday morning i started itching really bad and it went away. Later on i was out with some friends my lips began to feel really tight, when i looked in the mirror my lips had tripled in size. Now today im still itching, my breathing has been slightly laboured with my voice being horse and have developed red raised blotches on my skin.

Im getting a bit worried as this has come about after no lifestyle changes, no dietary changes. Nothing and i have no clue whats causing it.

Im leaving for a festival this weekend so wont have a chance to see a gp. In the meantime ive been taking antihistamines.

Any ideas of what could be causing it or the best things to avoid until i see my doctor?

Thanks.