Portal Bug

I went into the nether to deposit some of my valuable materials and when I tried to come back out of the nether, it just said,"building terrain." It continued to say this as I hear tick damage until my friend noticed that I dies from drowning even though the portal was above water. I tried to find my lost things and it was nowhere to be found! I found this annoying and I did not want it to happen again, If it is made possible, I would like this to be fixed.