I'm sorry to hear that you fulfilled these orders through Shopify. You must place the order through Oberlo so that you can pay the cost to the supplier and they can ship it!
However, it can definitely be fixed. First, you will need to go to your order in Shopify and press more followed by cancel fulfillment. Then, head to your Oberlo Orders. Please make sure you have the Oberlo Google Chrome extension installed. If you do, you'll be able to see an orange order products button! Once you press this, you can pay the supplier and it will be processed.
If you're having difficulty during any of these steps, please email our support at firstname.lastname@example.org. They'll be able to jump in and make sure everything was processed correctly!
Most importantly, don't stress! This happened to many beginner dropshippers (including myself). Once you've got these sorted, you'll know the proper process for the next ones.