Starting over

I had hoped to have my sister-in-law's present (one of them)completed by yesterday (Sunday). Well I can tell you now that.......it did NOT happen! I will have to take out and re-do about 10 rows. All was going well until I got to a row where I had to start decreasing and I should have ended up with 72 stitches but had way too many. I do not understand how I get extra stitches when I just stitch on the same stitch. So I am going to undo those rows and start them over and count every single stitch and hopefully I will be able to keep the correct amount of stitches and have it look good too. It is a bag/purse done in dc so I don't want any big gaps. I am using Lion cotton and this is my first time using cotton yarn. I love it and it works up quickly but it is so thin you can see if there are gaps. I am kind of obsessing over the purses I made for my nieces. The pattern suggested using cotton yarn but I used acrylic since my store did not have cotton in the color the girls like. I am hoping they like their gift. It is getting to crunch time with these gifts. I may have to re-think a few and change what I am making. The guys should be easier as I am buying their gifts. I have to wait until it gets closer until Christmas until I can go shopping though. B has a habit of not waiting and buying stuff on his own. I so hate that! And now my oldest nephew is getting the same way. Last year he told me what he wanted and then went and bought it on his own. I told him he was lucky I had gotten him something different and not to do it again. LOL!