current plan doesnt match expected and billed speed? super slow and laggy for the last 2 weeks since upgrading

So when i go to manage services it says i have the "400 mbps connect more" but when i look at my "broadband facts label" it shows i have the 1000mbps plan. i upgraded a couple weeks ago, and am currently on a new billing cycle as of 5 days ago, does this take another month to update? ever since i "upgraded" i have noticed that it is considerably slower, constantly dropping out, not fully loading pages, taking a long time to load, even watching youtube videos they lag every couple minutes and takes a few seconds to come back. it happens on my cell phone, laptop, tablet, smart tv, so im sure its not one of my devices.  i am running the xfinity gateway they sent me, with my router plugged into it as well for my mesh network, and it does it when connected to BOTH the xfinity gateway, and my mesh network. It is actually a lot faster using my routers, seeing ~140mbps on a speedtest vs 40-60mbps, and also 200-400ms ping through the xfinity wifi. this just seems unreasonably slow. i know the speeds aren't guaranteed but this is just terrible, worse than it was 2 weeks ago before i "upgraded". i restarted the gateway, dont pretty much everything i can think of but its just not helping. i may try hooking up my old modem and seeing if that changes anything.