Seeing that your SSD has 34% harddrive space left, is it possible you have filled your SSD to a point where it was lower than 25% free space?
SSD drives are different from normal HDD drives in regards of how it stores data. Whenever data is written to the SSD it will do so to empty clusters first. But it might not fill all sectors of a cluster. So per cluster there will be empty sectors. When a file is removed, it will use TRIM to mark clusters that are completely empty as new free space. This is how an SSD gets its speed.
If your space goes lower than 25% free, it is usually the point where there are no free clusters anymore. So files will be written to sectors on existing clusters, which means the files become fragmented. Due to this, when a file is removed, the cluster is usually not completely empty, and thus cannot be marked as free. Since accessing files over multiple clusters slows down access considerably, this is where the slowdown comes from.
To make your drive fast again, you first need to ensure you are having at least 25% free diskspace, and will keep having enough space, then find a defragger tool specificly for SSD's (normal tools won't recognise the different clusters, so make sure it is capable of working with SSD's) to reorganise the drive. This will make your drive fast again, and should only be performed once, then avoid having your space go below 25%.
Alternatively, you can try freeing/moving as much files off the SSD as possible, and then move them back, but this will not ensure that the speed comes back as some of the files that remain may still be fragmented.