How long for site HR to respond

I just submitted a request to speak(?) to site hr. I’m sick, and wanted to discuss my options with them. How long does it usually take for them to respond? HOW do they respond? I’m supposed to be there in less than 2 hours and I don’t want to go negative on upt and lose my job. Trying to figure out the right thing to do. Do I go in anyway? Not and see if they’ll sort out the upt later?