I’m sorry to hear that you’re stuck! You don’t have to cut the yarn if you don’t want to. It’s hard for me to see in the pattern (I only figure out patterns as I knit them), but you might be able to “carry” Color A along during those 5 rows of Color B by twisting it into the stitches as you go (i know you’ve already done those rows, and probably don’t want to go back, but as you continue on, you could). If you just pick up the color A yarn and start knitting again, you’ll get a “float” along the side of the work. I notice that the pattern suggests crocheting a border along the edges if you want to, which would hide those floats. You could also pick up stitches and knit a border, if you don’t feel like crocheting.
For now, you could cut the yarn, and have two more ends to weave in at the end. Then, as you continue on, experiment with “catching” that Color A yarn with some of your color B stitches so that the float will be more “tucked in” to the work. Or you could alter the pattern just a bit and add a color B border on the side, so that you’re actually knitting with it for one or two stitches each row and you won’t need to carry it along at all. If you do this, make sure you twist the yarns together so that you don’t get a hole in between stripes.
To summarize: the pattern leaves you some freedom as far as what to do with that yarn. Play around and see what you’re happy with. Feel free to ask me more questions if what I said was too confusing. writing about knitting techniques is hard