Week 2 is when ovulation will occur or would be occurring shortly depending on your normal cycle length and when you typically ovulate.
The main hormone present right before ovulation is Luteinizing Hormone (LH). LH surges between 24-36 hours before ovulation occurs and can be picked up with Ovulation Predictor Kits (OPKs). LH is surging when the test line on your OPK is as dark or darker than the control line and ovulation would typically occur between 24-36 hours after the first positive result.
The lifespan of the egg is typically 24 hours and fertilisation needs to occur within this timeframe for a pregnancy to occur. It is best to have intercourse within the 3 days leading up to and/or on the day of ovulation to have the sperm waiting for the egg to be released for optimal chances of fertilisation.