Starcraft 2: Defending against proxy 2-rax (and early aggression in general) as Terran

TLDR: How can a (Terran) player in the lower leagues successfully defending against rushes / early pushes? In this particular game from earlier today, the opponent is a Terran who did a proxy 2-rax. (I didn't think I could defend so I quickly gg-ed - maybe I shouldn't have given up so easily?)

I am not so much looking for build orders. Rather, I'm looking for principles/guidelines that will increase my chances of defending against early aggression when I'm following a macro-ish build (12 Rax / 14 Gas / 18 CC). For example, potential factors which come to mind include:

• Building placement
• Worker micro
• Resource allocation (i.e., curbing worker production in favor of army production)
• Abandoning ship and going to a new base (which wasn't feasible on this particular map - see game below - but it might be relevant on bigger maps).
• Other factors not listed here?
• A combination of the above

Longer version:

Some background:

Why do I think it's important that I mention I'm in one of the wood leagues? I think it might influence folks' responses/advice given that:

• scouting information is unreliable
• certain strategies/tactics which may be ineffective in the higher leagues may work in the lower league

The game in question:

A quick recap of the game (a replay can be found here - same link as above):

• TvT on Vaani Research Station
• I start the game planning to do the only build that I know (as I am in one of the wood leagues after all): 12 Rax / 14 Gas / 18 CC
• I send out my scout SCV after barracks is complete and I notice that my opponent's ramp is partially walled off with 2 depots (i.e., no barracks). Aside from a CC (which isn't in process of upgrading to an orbital), he has nothing else in his main. I checked both expansions and he has nothing. Smells like a proxy 2-rax.
• To be honest, my intention behind scouting is primarily to develop multitasking ability (i.e., macro-ing while not looking at base, etc.) as I've been told time and again that it's not worth acting upon scouting information in the lower leagues given that the concept of build order often doesn't apply. (I subscribe to the notion that having more stuff - as opposed to the right stuff - is enough to win at the lower levels.)
• At the 6 minute mark, I am paid a house call by 10 or so marines. Seeing as how (i) my army consisted of only 2 marines (the reactor just finished on my first barracks so it hasn't been producing for the last minute or so; the next two barracks are still under construction) and (ii) I don't really know how to handle such early-game situations where I'm massively outgunned, I quickly gg-ed. (Perhaps I shouldn't have given up just yet?)

(The replay confirmed my opponent did a proxy 2-rax. And based on the spending-stats on GG-tracker, he executed quite well.)

A few comments on the game:

• My macro (as measured by spending quotient) was worse than usual in this game because I was distracted by something in the room (which is why the depot went down a few seconds late which had the typical snowball effect). Regardless, I think my situation would have been the same even if my production cycle were 30 seconds ahead of where it ended up being (i.e., if I'd had 4-5 marines instead of only 2 marines).
• Regarding building placement - my preference is to not wall against Terran because marines can attack my wall with impunity (flawed thinking?). FWIW, I think a wall would have bought me another 10 seconds max so it doesn't seem like it would be a game-changer - but let me know if you think differently.