Printing trouble (most likely leave long the bed)

[trench]

Hello, I just friend printing a 2hr print with supports and my support plate started to get stringy and messed up (check pics). I noticed that the left extruded at one point knocked the support plate and brought a tiny bit of plastic up so I think that might be the problem. I've been having a little but of trouble in regards to leveling the build plate. Anyone know what's wrong? Is it the build plate? If so what's the correct way to adjust and set it?

thankyou for any help in advance!

-Trench