Answer:
Pregnancy caused by pre-ejaculate fluid, contrary to popular belief, is extremely rare. This does not mean that it doesn't happen, but pre-ejaculate fluid does not typically contain live, active sperm cells. The only time live, active sperm are present in pre-ejaculate fluid is when the male has not urinated since his last ejaculation to clear his urethra of any sperm that may be hanging out in there. So long as you're certain he did not ejaculate inside of you, you're probably safe.
Implantation cramping of bleeding does not usually occur until two weeks after intercourse, as this is how long it usually takes for implantation to occur, so it's just a bit too soon for you to be experiencing that. However, if in about a week or so, you start spotting, this could be implantation bleeding.
I suggest you try going to a clinic like Planned Parenthood and getting on a hormonal birth control of some kind. Planned Parenthood will be confidential, and will usually charge you only what you can afford (according to your income). To find one near you, go to www.plannedparenthood.org.
I just wouldn't worry about this too much. Remember that stress can cause your periods to be more irregular, and that worrying about it will do you no good. I honestly think that there is a very, very slim chance that you are pregnant.
DID YOU EVER GET THE CONDOM OUT THAT COULD BE THE PROBLEM.
The best way to answer this is to get a home pregnancy test.
hahahaha these are consequences of sex. should have thought about it beforeeee you did the deed. and if it came off, it was obviously never on right to begin with...so anything can happen, and condoms are not 100% anyway;
It is possible to become pregnant from this, but unlikely. You can always take a test or two to be sure.