As dalto already mentioned we really need to know what you did. Exactly how did you make the changes. If you expanded your swap by shrinking another partition we need to know exactly which partitions you modified.
Please do not make any further changes to this drive if you want to have any hope of recovering your drive. If you have modified partition tables, any data that was located near modified partition boundaries is likely corrupted. If you are lucky the majority of your data may still be intact and recoverable (depending on what you did).
The safest method of recovery is to copy block for block all data currently still on the drive to another larger drive using dd. Then you can use the program testdisk to attempt recovery from the duplicated drive.
Recovery directly from the original drive can be attempted using testdisk, but that reduces your chance of a successful recovery operation. This process can take a very long time depending on the size of the drive involved.