Using symptoms to determine if you're pregnant is really unreliable. If you absolutely must know if you're pregnant, wait 10 to 14 days after the sexual encounter in question then take a pregnancy test using the first urine of the morning (it's the most concentrated). False positives are exceedingly rare, so if it's positive, then you're mostly likely pregnant. You can go to the doctor for a follow-up blood test to be sure.
As for PMS symptoms, there are a variety of remedies out there to help you with that. These range from the ever-popular Midol, to various herbal teas, meditations, or chocolate mini-binges.
So, did you have a real pregnancy risk? Figure it out with: What's the Risk? Easy Pregnancy Risk Assessments