Sorry for the long delay. The reason I asked you to check the drive size is because once the drive starts to get full it will slow down your Macbook. You currently have about 10% or less drive space.
Ideally or what is recommend is at "least" 15% drive space open for the computer to function properly. I recommend you try and go through your macbook and find any applications you can uninstall/remove.
Also you may want to consider using a external hard drive for media such as pictures, music, videos. This would clear up much needed space on the macbook.
Please Repair Disk Permissions on your hard drive. Click on the Search (maginifine glass) top right. In the box type in Disk Utility
and hit enter.
A box will appear, click on Macintosh HD on the left pane. Then click on Repair Disk Permissions.
Also download and install Ccleaner. It is free cleaning utility which will help remove temp/junk files. This should clear some space as well.
Click here>>>Ccleaner Download
After you install open the program and click on Run Cleaner.
When your done, see if this has improved the performance of the Macbook.Let me know how you make out. Reply back to me BEFORE selecting any negative rating. I will answer your follow ups.