Resting during a medical abortion is not mandatory, although it is recommended for you to be more comfortable.
If you are using Mifepristone it is likely you can continue with your normal activities the day you take it and leading up to before you use Misoprostol. Once you use Misoprostol you will experience cramping and bleeding. Many women prefer to rest while the cramping and bleeding is intense. Usually after 48 hours of using Misoprostol all the symptoms decrease. Depending on how you feel you may want to do your daily activities or you may prefer to rest. Again, each woman has a different experience so it all depends on how you are feeling.