I don't know what kind of blood test they did, or what they did it for, but I think unless they are looking to see if you are pregnant they probably won't know if you are pregnant or not. Same as a home pregnancy test (the kind you pee on) won't tell you if you, say, have marijuana in your system. (I'm not saying YOU have marijuana in your system, but I'm just making an analogy.) If they don't specifically test for pregnancy hormone in your blood, they probably won't know if you're pg or not.
The good news is home pregnancy tests are easy to get, or you can go to Planned Parenthood and I think they give them for free. If you are far enough along to have symptoms, you are likely far enough along for a test to come up + of you are pregnant. (It usually takes about 2 weeks from the time of the sex that led to the pregnancy for a home test to show a positive.) You're probably fine, but take the test and put your mind at ease. the earlier you know, the more options you have.
Whatever the result, try to take this little "scare" as a learning experience. I wish you the very best of luck!