There isn't really much you can do as LB other than 1 shotting minions with your W once you have enough AP. That is just one of her drawbacks is she can't CS worth a crap. How many assist did you get? From what I have noticed, champs that can't CS well can make up for it by having more kill participation. If your team has say 30 kills and you killed 13 but didn't assist in the rest, it isn't that great, but say you only killed 8-10 but assisted in 10+? That would be graded better since you were in a higher % of the kills.
I would probably focus more on CS than getting poke or kills. By all means kill the enemy if you are capable or they position bad, but if you have 2 minion waves pushing towards your tower, it may be wiser to just W them instead, just doing that every now and then alone should up your CS a lot.
This is just coming from someone that faces LB and noticed a trend with her. Most times when I lane against her I care little for killing her and mostly on pushing her minions, that means less cs for her when its already hard enough for her to cs, but also free damage on her when she gets ballsy and decides to W over the minions and takes 100+ just from minions. I lost count of how many times a cannon wave or even 2 minion waves were there and LB tried to blow me up, only for her to almost get killed just by the minions alone, they are no joke early on, and how squishy she is, its pretty easy to see how they can be a factor in her death. It woulda been way more useful if she just W the minions and took them out than try to get a kill on me. Even if she succeeded, the amount I can farm and how she lacks it often means it doesn't help her much since I probably have more gold than her anyways. I again have seen this in LB, sure it might look scary if she is like 8/1, til you see her CS which is like 50-70 by 20 minutes, then I kinda laugh when I might be 0/3 or something, but have nearly 200 or even more CS and can still go toe to toe with her.