Just got my BFP...now people are saying it might not be real??

Your friend has no idea what she is talking about. Unless you received an HCG trigger shot there is no way a pill or antibiotic would contain HCG in your urine. I would definitely 99.9% sure you are pregnant. Just try to relax and have your blood test on Wednesday to confirm. Don't worry no pills in the world could cause a false positive.