What's a nickname that a lot of people call you?

The people on here who know me might find this unbelievable, but a lot of people in real life like to call me sunshine. 0_0
I am the least sunshiney person in existence so I'm 100% sure it's a sarcastic nickname but so many people call me it that I'm always like "why?!".
For example at my PT place the people there greet me like this, "Hey sunshine!" "How is our sunshine today?" "Our sunshine is here!" "It's our little drop of sunshine!". One of them actually thought my real name was Sunshine because they never call me by my actual name just Sunshine. >_<
Kill me lol