I think more should pipe up about this
I'm 30ish weeks and have gained the same, when I voiced my concerns to my MW she brushed it off, there is a terrible culture in this country of normalising excessive weight gain in pregnancy and I wanted some support from my HCPs about controlling it
in the uk the guide is that you gain 2 stone IN TOTAL (most being in the last few weeks) and I'm already nearly there with still a couple of months to go.... However IMO that's still over generous as in other countries its more like 1 stone
I gained 4 overall last time.. it made labour shitty, it made looking after a newborn stilly, it made recovering from emcs shitty, NOBODY commented on my weight gain during that pregnancy and I bloody wish they had, its their job surely!
I am angry at being brushed off about my concerns of going down the same road again this time
you need to be fit and healthy for labour and life with a newborn, but my sodding MW treated my like I was just being vein by being worried about it! 
OP, do keep an eye on it, it really does make things harder if you gain too much!