What Causes A Delayed Period,tiredness And Enlarged Breasts?

I came off the pill a month ago and yet I have had no period. I know its meant to be a little while before you have one, but I've only been taking them for 5 months. I get cramps rarely. I have a raised temperature all the time. If I were pregnant I would be 2 1/2 weeks, cause I had unprotected sex 4 1/2 weeks ago (just after I stopped taking my pill)
I don't feel sick very often but I get tired very easily, I feel exhausted all the time. I don't sleep very well and It's painful to sleep on my stomach. My breasts have gotten bigger and grown a size in 2 weeks. What is going on? Am I pregnant?