i have common cold for three days already. is it contagious?

i got sore throat on 25th dec morning. from 26th, i started sneezing non-stop and have runny nose. today on 27th, my throat is fine but i get either blocked nose on one side and drippy nose on the other side. i also started coughing a bit. ive seen a doctor already and she said i only need to get some rest and use nasal decongestant if the blocked nose is very problematic.

my question is, is it ok for me to go to work tomorrow? i took a day off today because im afraid that i might pass it on to someone else during work esp. since my job involves dealing with customers on a regular basis. and i read from some websites (although i could be wrong) that common cold is most contagious within the first three-four days!

thanks!