Okay I'll try to let myself get paranoid, thank you!
you cant take a test until youve missed a period. So yes its too early. And its also too early to have these symptoms. They usually dont appar until the next month or 2. So your mind is definately playing tricks on you. Take it easy, rest and wait to see when the flow comes. If could also be that you may have a uti. might want to go to the gyno and have your pee examined
It is true that the precum contains sperm, but him putting a condom on shortly after starting is great in your favor!
Just wait until you've missed your next period more than usual. Many tests say that they can give you accurate results about a week before the missed period, but I'd wait until after you've missed it.
Until then, try not to stress about it. The stress can make a women's cycle go haywire, and you could just end up being late from that.
Any 'sypmtoms' or signs of pregnancy wouldn't be affecting you yet if you were pregnant.. And never count on 'symptoms' to point to pregnancy, because many women never experience anything like morning sickness or mood swings.
I'm thinking you're not pregnant, but just keep an eye out for your next period, and just remember to not stress about it yet!
Good luck and Best wishes! :)