Huh? Sciatica is nerve pain - usually from your lower back going down one leg. Don't know what that would have to do with someone looking like a flamingo or her wedding dress being too tight.
Mono is definitely glandular fever - short for mononucleosis. And strep is short for streptococccus. Ok, my spelling's not that great but I think the Americans like naming things based on the actual name of the virus or bacteria involved. When my friend's little girl had cellulitis my dad (a pediatrician in America) kept asking,"But is it strep?, Is it staph?".
Also, I don't think strep and tonsillitis are strictly the same thing - you can get an infection/inflamation of the tonsils that is not caused by strep. I used to get both strep and tonsillitis when I was little (in the states) and eventually had to have my tonsils out. Did the trick though!