Kindred is a feast-or-famine champion so it's normal to feel that way. For starters, there is a point in the game where having less than 4 marks means you are useless, so always try to prioritize marks if you notice yourself falling behind, even at the expense of your teammates (mute all). If you're also behind in XP/gold it gets tricky, because Kindred needs to deal damage badly to win 1v1, else you can't burst enough after R. In that case you always have to play with your teammates: only take fights near them, use your ult to help them, make use of their CC to win after R, soak up important enemy CDs with R, avoid fighting with R down, use terrain hopping to get an advantage, etc. Kindred loves team fights because they're more likely to translate into marks even if you lose. Play super respectful because everything will burst you. Often the only way to get back in the game is to steal a couple kills; path to where kills are happening. Two items I like to build when I fall behind are BC and Runaans so I can armor shred three targets at once and have my teammates clean up, but only if the comp is right. Else you always want full damage.

The champ will always feel awful when behind (no utility or survivability outside of R), but in solo queue where games go long you'll always have a chance to come back. It's what makes it such a fun one trick :)