[escape_thereal_world]

Lissa is correct. Having sex, especially more often than you normally do can affect your period.

Also, even if you have been on anti-depressants for a long time and switch medicine, it can change the chemicals in your body as they all work differently. So it could definitely be the Lexapro.

As for testing. If you had sex within the last week, and you suspect pregnancy from that, it is impossible to get an accurate result on a test yet. General rule is to wait at least 14 days after intercourse. However, each person can ovulate (when you are most fertile) differently so you usually should wait at least 4 days before your next expected period.

For you, this period is too soon to test as it hasn't been 14 days. So wait until your next expected period. Or if you use an early pregnancy test, you can test as soon as a week before, though most accurately 4 days before for around 60-70% chance of a positive result (dependent on the brand, read labels).

Also, if he uses the restroom and doesn't ejaculate anytime between the restroom and the time you have intercourse, it is very unlikely, if not impossible, to become pregnant. Withdrawal method, if used correctly, has a failure rate of 4%, whereas condoms have a 2% failure rate. Source - read under "How Effective is Withdrawal?"

However, with you just switching medications and missing your period only a week after intercourse leads me to believe your missed period is not due to pregnancy.