Playing/building Irelia when behind?

Title. I love to play Irelia but in some matchups I get behind early and I become a free kill for the enemy every time I'm in lane and I feel like there is absolutely nothing I can do.

My main question is how should I build her in these scenarios. Normally I would rush guinsoos when ahead but that wouldn't help me at all when behind

Also if I am really far behind should I just sacrifice all of my cs and stand within XP range? Is there something else I could do instead?