@Sara5699I can't see your listing to comment, but have you perhaps set a discount based on length of stay, or do you have a discount set up because you're a new host? If you're unsure, go to your Listing tab on your dashboard, then select Pricing. It will show you any discounts that are set up for length of stay. Your calendar should show any special offers in place.
Your days may have been blocked because you didn't accept or decline the reservation. You have to take action: if you just leave it, Airbnb assumes that you don't want to book those dates and blocks them out. If you are a new host, I would just call or message Airbnb, explain what happened, and ask for them to unblock the dates. I like messaging them on Twitter @airbnbhelp. It's easy to lay out your issue, and wait times if you call in are pretty long at the moment.
Your strict cancellation policy has no bearing on discounts. It's totally unrelated.