Finding it really hard not to feed as Zyra/Brand

No clue why, with these two champs I just have a shit ton of deaths every game, even if I do even it out with kills. It's not that I'm trying to do it on purpose. I do my best to position properly and grant my team vision, and escape ganks.

I literally can't avoid having less than five deaths. Is this a mentality issue, and does anyone have any tips?