Sudden weight gain 36 weeks pregnant ?

In 3 days I’ve put on 2.5 kilos. I haven’t been eating crazy and I don’t even look like I have throughout my body! Google tells me gestational diabetes which I don’t have and pre eclampsia which i had in my first pregnancy which the weigh gain was all the fluid retention throughout my body, the swelling was crazy! But the only things that are actually puff are my hands and slightly face but I haven’t put on that weight in my hands and face 😂 my back has started to ache pretty bad over these couple of days as well. I’m aware that baby gains weight more often in the last weeks of pregnancy but 2.5kilos doesn’t seem right. Thoughts ? Tia 🌸