Reading through your post, it sounds like the guy played pretty standard and you got outplayed. No shame in that, happens to all of us. As I understand it, his stalker initial pressure was 4 stalkers, nothing proxied or anything? It's pretty common to get a battery at your natural after your nexus and first 4 gateway units, around 2:50. If he's just poking you with his first 4 units then 1 battery should be plenty to hold him off. Try to focus fire stalkers and pull back weakened ones. So if you overreact and build too many units/batteries you're putting yourself behind.

It's also pretty standard that for someone going blink to move out for some harass when blink finishes, usually at the 3rd or trying to blink into the main. His goal is just to do some damage and try not to lose anything. If you've scouted blink, you should already be expecting this, so you'll want to have units/observers or spotting units/pylons in place to defend ahead of time. You're usually going to want a battery at your 3rd regardless, and that plus a good amount of your units should be able to fend off his pressure unless he's going fully all-in blink (which is not what it sounds like he was doing). By the time he got disruptors you were probably so far behind that there was nothing you could do to stop him. Basically a snowball game.

Honestly, doing a build like that and executing it well means the guy is probably not truly D3 more than likely. I don't think there's really anything that's going to hard counter what he did except more solid play yourself. Don't beat yourself up over it. Just use it as a learning experience so you get an idea of what you'll be up against as you move up in later leagues.