relax already before you have a stroke.
you're just going to have to wait until Monday to find out
if they did send a letter, you wouldn't even have gotten it yet - a formal written offer letter is usually sent after a verbal offer has been tentatively accepted by you.

maybe the phone call was for a second interview with someone else

stop worrying about it

if you freak out about such a little thing like that, how are you going to handle real crises in your life and on the job?

I had a job interview yesterday, and i got a missed call on my phone from them today. I also received an email today saying please could I call them back. But when i rang in, i was told that the lady i need to speak to (head of HR) has gone home for the weekend, and i need to call her back on monday. But i was impatient so i actually rang the Head of Administration, who was the person who interviewed me, and asked her what it was about.

BUT she wouldn't give me any info, just said i need to ring back the head of HR on monday!!!!!!!! aaaaaaarrrrrrrggggghhhhhhh i can't wait that long!!!!!!!!

my question is: do you think i got the job, or didn't? because if i didn't, wouldn't they just send me a letter instead of phoning/emailing asking me to ring back? but on the other hand, if i did, wouldn't the head of administration, who actually interviewed me in the first place, have told me that i got the job????????????