It is maddening when something harms you but no one can see it. Pain is often invisible: what you struggle with on the inside may not show up on the outside. Mental pain, emotional pain, is among the most grueling, because it does not call to others for help the same way that physical pain does. Sympathy and aid come naturally when you see someone who has a bandage or a cough. Saying that you are not feeling well with nothing to point at is immensely frustrating.
Anxiety and depression are like icebergs. They show a little bit above the surface but are much, much bigger underneath. The palpitating electric dread of anxiety may be only hinted at in keeping the eyes away and a quivering tone. Depression is even better at hiding itself; the hollowed-out sense of self is quiet by nature.
What does it look like when someone is in distress? How many times have you been able to spot it in someone when they were hiding it well? It can be hard to do, as we are all trained to hide our feelings and our pain. This article describes what depression looks like in others in detail. It can be helpful to consider when you are going through it yourself. You may have more allies than you realize.