Is this pseudobulb rotting on my Psycopsis?

[Wade Coleman]

So I recently went on a week long vacation back home and ever since I’ve come back, my poor Psycopsis has been slowly deteriorating. It started with the new growth it had been working on for about a month or two. It started to yellow and then the entire growth was to the point that I could easily pull it off. Then the leaves on the smaller pseudobulbs yellowed and died. I now have the three biggest leaves still in tact, but I noticed what looks to be rotting on the largest pseudobulb. The bulbs also aren’t plumping up no matter how frequently I water. I have NO IDEA what happened over the week I was gone. All that it had to endure was a week without water, could this really have been the root to all this? I’m not sure how to stop the degradation of my plant. Can anyone help me? Why would my plant that has been healthily growing for me for 5 months all of a sudden start rotting away?