PLEASE help me identify these flying insects; infestation galore!!!!!!!?

Ok so tonight I was closing up my store and shut the A/C off and decided to open the door to air out the smell of the cleaning products I used to wipe down everything. A customer walked in and started flailing his arms..I walked towards him and I could NOT believe my eyes..it was a swarm of these flying insects all over the floor, on the beverage glass doors and just up on top by the ceiling lights!!! Anywhere there was light they flew around...omg I was going crazy I have NO idea where they came from it was such a horrific experience. I had no bug spray I've never had a problem like this before so I took my bleach water spray bottle and sprayed all that I saw. I've been going crazy all night doing my research trying to find out the name of this flying insect but I just can't seem to find out anythinbg about it. It looks similar to the usual house fly but it's thinner and longer. It has long white wings. The body has thin stripes of yellow/orange color and when I killed some of them, this yellow sticky stuff would come out..not a lot though. It's driving me crazy and I'm my room I think I'm hallucinating lol I keep thinking that there are bugs flying around me but there aren't..I can't get this sight out of my mind. Oh and another thing I wanted to add was they aren't that fast. You know how when you see a house fly resting somewhere and it sense you moving towards it,it flies away so fast? Well not with these..they just chill there and don't flinch. Please if anyone can help me identify what these bugs are I would REALLY appreciate it. Thanks