Not having problems scouting the rush. Having issues knowing whether I'm ahead after I stop it, and how to properly stop it so I'm gauranteed ahead.
You tend to want to make ur pool roughly the amount of time after it takes for his zerglings to reach you. If they take like 10 seconds to reach you. You can probably build one more drone than him. Thus putting you ahead economically just barely. (this will add up over time). Then make your pool just barely 10 seconds later than him. That way you have your lings up, as he hits you. and you have a higher drone count. just keep spamming lings, while you're spamming lings you should eventually make enough for a queen at some point. make her, If you successfully stopped it. Send in your lings just to scope out the situation if he's got more than you. (which he shouldn't by the time he gives up on trying to take you out early you should have a hundred or two hundred mineral lead.)
what you can do if he keeps on trying to attack you. and you got a slight lead in kills. You can try sending 6 lings off to the side. somewhere maybe camping at a xel'naga tower. once you see his next little wave coming to try and finish you off. you can send those 6 lings into his base. (Or less just enough to do dmg to his Drones while he's away). And leave enough in your base to stop the attack.
If you want man I we can play 1v1 ZvZ and I can keep trying to cheese you. So you can try and practice stopping it. But you'll need to send that early scout, even though you know i'm cheesing otherwise you're cheating yourself to learn because that early drone scout is technically you losing quite a bit of minerals to see cheese.
Also there have been instances where I leave my drone hiding at the side of his base when his lings hatch and head toward me. I'm usually just making my lings as his hatches. and when I get 100 minerals I'll pop that drone into a spine crawler in his base. (If it fails no biggie cancel it just before it dies.) Generally if he's just about to hit your base. He's rallied his hatchery to your base, and is macro'ing his base while micro'ing. So he won't see your spine crawler building if you try to take advantage of that timing.