@dunc thanks for the suggestion.
Actually, the wifi issue mysteriously fixed itself after 6 days (yesterday). I did not do anything special except restarting my computer every morning to check the Network to see if the Wifi option appears. That is because I read in 2 different threads that it happened to them.
I plugged my iPhone into the MacBook for 6 days to use the internet. I in fact went and got myself a wifi dongle but the wifi reappeared before I'm able to make it work. The wifi dongle needed a driver installed for Macbook vs plug and play for Windows.">Another guy resorted to using a wifi dongle, and after a few months, his wifi worked again.</a>
I plugged my iPhone into the MacBook for 6 days to use the internet. I in fact went and got myself a wifi dongle but the wifi reappeared before I'm able to make it work. The wifi dongle needed a driver installed for Macbook vs plug and play for Windows.