how often do you water that plant and how much water do you give it?
i would first repot it right away into a much bigger pot and use the same soil to avoid any further stress. it does look like a water issue at first glance but there also seems to be sone nutriant issues too maybe too much or too little.
how often do you feed and how much do you feed and what do you feed it.
from what i can see these are the key factors but there might also be something ive forgot to mention. hope this helps