Help! Disaster! also, 'importing' databases on mac

I have just tried to get to work on my home computer, but I can do nothing at all. Any file with php in it opens up with the php code all over the browser, unsystematically spliced into the html (which still seems to be working fine). I have not changed the code in any way from before when it was working fine in the lab. I have apache running and moved the files into the htdocs folder, but the behavior remains the same. I am at a complete loss for what to do and panicking becuase I can't make any progress without figuring this out. Help!!!

In better news, I had a breif moment of terror when I discovered there was no "import" function in my phpmyadmin (I use a mac, an old one), but I discovered that the .sql file I exported at the lab could be opened as a text file and the commands it is made up of copied right into the SQL queary form (after creating a databast to put them in) and the tables and content show up in perfect form.