How do I retrieve my contacts from SD card on my HTC Droid? My photos and calendar already went to phone.

Don't sink in and feel bad, it could only be a simple technical error. Instead, search for basic troubleshooting steps that can help your memory card recovery. There are different issues that may affect the memory card.
·If the computer is able to read the memory card but no images are showing or an "error message" appears, try ejecting the memory card properly by right clicking on your mouse and choose Eject. Do not just remove the memory card right away. This can lead to a permanent data loss which is irretrievable.
·Try using a USB memory card reader and open it. In this way, you can check if the problem is caused only by the card reader or the memory card itself. If the memory card is accessible upon using the USB card reader, then it is just caused by a hardware problem.
Most memory card recovery is done using third party software. This will include scanning, recovering and saving your lost files and images. Data recovery software offers better and convenient solutions to memory card failures.FoneDog data recovery software is very ideal to use because it is the most trusted software in this field with a proven result. You can even try the free version to check and preview its capabilities but with limited options. You can maximize its features by upgrading to its register version to enjoy recovering those fun memories.
·You can simply runFoneDogrecovery software and connect the memory card.
·Once connected, scan the memory card. It will show all the file types in the memory card. Choose the file type you want to recover.
·After selecting the file type, scan the software for any deleted or hidden data inside. The scanning may take few seconds or depend on a load of data or photos stored on the memory card.
·You may pause the scanning once you have the needed images.
·You can now preview the lost or hidden images. In this part, you may select and check the images you want to recover and click "Recover to computer" to save the images to your desktop folder.
More information you can see the guide: How to Recover Deleted Photos from Memory Card

Use AppMonster application if your phone is rooted.