This is Hamlet's statement that he wishes he were dead, that his body, all too physical, could just melt away "into a dew" or that God had not forbidden suicide, "fixed his canon against self-slaughter" as he will say later. He has lost all interest in the things of this world ("weary, stale, flat and unprofitable" says it all). What was once, by implication, a flourishing garden is now gone to seed with only things "disguisting and decaying" growing there.
This tells us that his depression is very serious. It also tells us that he does feel very isolated and alone in his grief: "an unweeded garden / That is going to seed." He has lost interest in the things that once gave him pleasure (a classic sign of depression), and he is contemplating suicide, stopped only by the fact that he just can't "disappear," and that God has forbidden him to act on his desire to die. And this is a theme we will see developed in other parts of the play.
O that my too, too solid body would melt,
Thaw, and change itself into a dew!
Or that the Everlasting God has forbidden
Suicide! O God! O God!
How weary, stale, flat, and unprofitable
All the habits of this world seem to me!
Shame on it! O for shame! It is an unweeded garden
That is going to seed, only things that are decaying and
Disgusting grow there. That it should come to this!
Only dead for two months! No, not so much, not two.
He does feel isolated. He can't understand how his mother could remarry after just one month ("No, not so much, not two") after she lost her husband, Hamlet's father. He is grieving for his father and angry at his mother. He feels betrayed by her and is trying to come to terms with what has happened.
Hamlet is suffering because his mother is getting remarried and on top of that she is marrying a killer that committed a crime. He killed his brother. Claudius is making it hard for Hamlet.
hamlet's in his soliloquy tells abouts his despair ......he has lost faith in his relations and he wants to die. however, this scene also shows his christian virtues that he can not commit suicide as it would result in his eternal damnation. furthermore this soliloquy shows how the satus of women has fallen in hamlet's eyes...he can not believe that his mother who really loved his father has married is uncle so quickly...