Good for you for sticking with it. As everyone else is saying, the more you knit, the better you'll get at it. And, the last stitch being lose is just the way of knitting. I've heard it explained before it's because that stitch doesn't have another stitch on either side to hold it so it will always be a little looser than the rest of your stitches. But, when you're finished with the project, unless it's a scarf or something like that, it's usually hidden in the seam. And even if it's not, it will not be that noticeable.
As for English vs. Continental, you do whichever way you're most comfortable with. I've been knitting over 30 years and I can do both ways, but I prefer English. I switch back and forth sometimes in the same project, but I always go back to English. I taught a coworker of mine to knit and I showed her English which was the way I knit so that's how she learned, but she now knits Continental and loves it. There is no wrong or right way to knit as long as you're doing the stitches correctly. Since you now know knit and purl, you can do just about anything because that's all knitting is...knit and purl...but it's the different things you can do with those two stitches that make this so much fun. Enjoy it...don't let it get you all flustered or upset. Do like you did and put it away for a while and when you come back to it, things will work out.