Here the speaker describes a blanket that works like armor. It covers them and hides what they feel, so from the outside they seem happy. Underneath, the pain keeps building, pressing and throbbing against the blanket until it can't be held in any longer.
When that moment comes, the speaker finds a cold, dark place, somewhere private, and the blanket breaks. The tears that follow are described as rain, washing away not only pain and worries but love too, which suggests that holding everything in has numbed the good feelings along with the bad.
Then it all goes back to normal. The speaker wraps the blanket around themselves again and keeps walking a "lonely path." The last line, "Smiling, but broken," sums up the mood: quiet, weary and isolated. The poem seems to be about hiding sadness behind a cheerful face, and about how crying in secret brings relief without really changing anything.