I don't know how helpful I'll be here, because I'm new to this whole thing, but I just did a ACV rinse a few days ago and I don't think my hair is too dry (its not any drier than normal, at any rate, haha!). I'm wavy (2C), so my hair may be different than yours, but maybe I did something different that could help you?
You said you did a "vinegar" rinse--I just want to check and make sure you mean apple cider vinegar? I followed the recipe here
but there's one on the livecurlylivefree.com website too. I didn't use the whole bottle of it, just enough to get my entire scalp wet.
The livecurlylivefree site has you leave it in, and the NC recipe says to rinse it out; I rinsed mine out and then went through my (new) routine: cleansed with a (cleansing) conditioner and then deep conditioned. I have no idea if that was the proper way to do things or not, but it seemed to work! I had horrible build up and it really did help.
I think they recommend only doing the rinse 1 or 2 times a month because it can be drying, so that might be part of the problem too--maybe the L'Oreal conditioner isn't moisturizing enough and the rinse dried you out some more. You might be better off switching back