If this is the case of your wife, I suggest to get her visited by an OG, and to do the blood HCG
However, to my opinion, if the testing is positive, it is pregnancy
for sure. Usually, OTC pregnancy testing are accurate and less chances for false results. The sore breasts are due to pregnancy and/or periods too.
If the pregnancy is confirmed through blood HCG, I advise to talk to her doctor about the effects of citalopram
All the best!