False positive question....

We have been trying for 2 years now and I got 2 strong positives. It worries me just because 24 hours ago I took an antihistamine, and online it says if you take antihistamines they can give you a false positive. Is that true? I want to believe the positives so bad, I just have never had a positive pregnancy test and have been so used to getting negatives. Anyone have any experience with this?