Help with knitting gloves

Hey everyone,
I’m knitting a glove on straight needles. Basically, I knitted the thumb and I’m now missing two stitches and I can’t work out where I went.

Before the thumb I had 84 stitches. Then I:

(right side) K54, turn, cast on 2 sts
P23
Work 18 rows in st st
K1 [K2 tog] to end. (12 sts)
P1 [P2 tog] to last 1 st. P1.
Break yarn, thread through remaining 7 sts, draw up tightly and join seam.
With right side facing and continuing stripe sequence, join yarn to base of thumb, K to end. (63 sts).

My problem is, I knitted the thumb nicely and I now have 61 sts in the order from left to right 28 sts then space of thumb then 33 sts.

I sense that my problem may lay in the casting on of 2 sts. When I did this, I cast onto my left needle and then knit the new stitches… was this right?

If I did accidentally knit my newly created stitches when I should have, can I cast on two more or otherwise make two stitches somewhere? whereabouts would you suggest as the best place?

Hoping that one of you pros can help me please! Thank you.