Sudden hives post 5dt

We did transfer on Nov 5th and have been taking progesterone shot since oct 31st, on 6th I got little itchy around shot area, on 7th itching spread across buttcheeks and on Friday I had red bumps on buttcheeks, as I never had allergies and reactions I thought it's due to dryness, on Saturday I had small red bumps all over body, which I thought will go away and then on Sunday evening I took progesterone shot and next morning couldn't recognize myself in mirror:

I contacted fertility clinic on Monday and they prescribed Benadryl since then I am on Benadryl, some of these red spots getting better but some new ones are coming back. Some of them are on my hand and feet those are most painful.. my finger tips are sweeping too and walking on feet is painful.

Has anyone experienced something like this?

Any recommendations how to take precaution to not to let this happen again?

I am confused why this happened I never ever had and allergic reactions or any allergies- need help