It looks like you're going to knit 52 stitches for the back of the sweater and leave them on the circular needle.
Then you're going to knit the 34 stitches for the right sleeve and work them on straights.
If there are stitches before the 52, then they are probably for the right front. One way to check is to count if there are the same number of stitches beyond the right sleeve as are on the circular needle before the left sleeve. Will this work with what you have?
And yes, you were supposed to cut the yarn after you finished the sleeve.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry