Overweight

Two days to my boxing match, scale before the training shows almost 3kg overweight. Tonight's session was intense but much shorter and I haven't lost as much weight as I usually do over the class. After training my weight was still a bit over my boxing weight.
When usually I am dropping at least couple of kilos below.
I've been running,even on Sunday,my usual rest day. (I did 5k charity race)
I've been training as usual and eating pretty much clean too.
Can I drop it?
Of course I can. That's not a big deal I can easily drop 2 or 3 kg on the day.
I have done it before. However I don't think that this is healthy and right way of preparation for the fight.
Especially as my fighting weight has been around 75kg for a long time.
My plan after training camp in Thailand was to drop down to 72kg walking weight and remain it. So my fighting weight would be under 70.
And I am still working on it but it looks like I need a bit more time and possibly some professional help from nutritionist.
Why would my weight suddenly jump up?
I can only presume.
There might be many different  reasons like lacking of rest and sleep, over training, working long hours...
I am not really looking for a reason as I believe that what I am doing at my work and training is still not my maximum.
I am still looking for the way to do more and better.
I think my next step is going to be visit at some professional nutritionist cabinet.