RPA form completed, submitted ucas application- heard nothing yet

I got an offer from Leicester uni and had to complete an RPA form to accept the offer. I sent it to them via email and haven't heard anything for two days. I met all the entry requirements but I'm getting paranoid that I won't get in? How long does it take for the unis to confirm offers using the RPA forms?

*i sent off my ucas application yesterday via my school and added Leicester as my clearing choice.