I sunburn so easily!

Hello.

All jokes aside, I will sunburn in 5 minutes while sitting on my sofa in my living room on an overcast day.

I am fair skinned with light eyes, light hair, and freckles.  I have always been sunburn-prone, but I seem to be getting more and more prone to sunburns over the last couple of years.  I now wear spf 45 from sunrise to sunset and reapply every hour.  If I miss an application and am near a window or outside, I will burn in 5 minutes.

When my face, ears, or arms burn, they turn an even red color and sting like a burn.  If my upper back, shoulders, or chest burn, they are blotchy red and itchy much like hives.

I have a lot of allergies to things like cats, wool, grass, and avocados, so my friends have started to joke that I'm also allergic to the sun.  That seems silly because if I were, I would expect to have been this photosensitive from birth.  Not to mention that sun allergy is so rare!

To my knowledge, I am not taking any medications which increase photosensitivity.  The only daily medication i take is take Clariten-D (an allergy med).  I use salicylic acid 0.5% on my face to control pimples.  About 8 years ago, I used Retin-A Micro for acne.  I know Retin-A increase photosensitivity, but I used for a year at most and only on my face.  I've never taken oral acne medications.

Sorry to be so long-winded!  Is there some sort of goofy explaination for my extreme sensitivity, or am I just a typical caucasian?

Thanks so much!