It is generally normal for the baby's heartbeat to not be detected at 5 weeks of pregnancy. The development of the fetal heart starts around 5-6 weeks, and it may take a few more days or even up to 8 weeks for the heartbeat to become audible on an ultrasound. It is important to remember that every pregnancy is different, and there can be variations in when the heartbeat becomes detectable. Your doctor will monitor your progress through regular check-ups and ultrasounds to ensure everything is progressing as expected. If you have any concerns or if there are other symptoms present, it is always best to consult with your healthcare provider for further evaluation and guidance.