Are you saying your actual BG is high or just that your Libre is showing you’re high when you’re not?
I don’t know if this is appropriate to your comment, but the Libre overshoots often in my case. If I have a very rapidly rising BG or I’m just high and continuing to rise, my Libre might reflect a value that is 30 points higher than my actual BG. Because of this, I know to test before I give myself a big correction. In general, it won’t ever tell me I’m high if I’m not, but it might show a 242 when I’m 214… something like that. I’ve noticed my G6 also can do this on the first couple of days but usually settles down. I once read somewhere, and @Chris would know if this has any truth to it better than I, that sensor that do not require calibration (which would be both the Libre and G6) often swing wider than actual values. In reality, I just keep it in mind, and if ever I’m not sure, I finger stick.
Have you read @DaveJ’s thread on alternative sites? (Please forgive me if that’s not DaveJ’s thread 
).