Depression leads to acts of kindness?

I have never read this play before, but I found it quite interesting that a lot of the drama unfolded in the first act. Shakespeare is known for all of his characters to be interested in one another, and he has them play out into scenes which you need a chart to keep everything straight. Antonio I thought was an interesting character. "In sooth, I know not why I am so sad. It wearies me, you say it wearies you" (1-2). He basically explains to his friend that he is depressed and he doesn't know why. His friend Salerio responds, "Your mind is tossing on the ocean, There where your argosies with portly sail" (8-9). His friend believes his saddness is due to his worrying about his ship not making it across the ocean.
Antonio quickly denies this and denies that he is in love. I don't believe Antonio is not in love. I think he has love for one of the characters but he has yet to come forth and confess this. In the midst of this he lends his friend, Bassanio money to woe an heiress Portia. "That in your knowledge may by me be done, And I am pressed unto it. Therefore speak"(159-160). he is very kind and makes this grand gesture. Sort of a "hey don't worry about it" attitude. This surprises me because when you are sad or deressed, you don't want to lend people money. Especially since his friend already owes you money. The only reason I would think is that he understands the concept of love. His saddness is derived from such an emotion. He is willing to make this sacrafice.
Towards the end of act 1 Antonio has to talk to Shylock who is a jew because Bassanio needs to get a loan from him since Antonios riches are out at sea. "For the which, as I told you, Antonio shall be bound."(1.3 line 4). Bassanio explains here to Shylock that Antonio is god for the loana nd can pay him back. Shylock is reluctant towards him beacuse he has bad ties with Antonio. When Antonio enters and they all talk he strikes a deal with the devil. They now have to become friends and if Shylock doesn't get his money Antonio's life is on the line.
In conclusion I believe Antonio values friendship and went through all this trouble for his friend to find love with this heiress. Only a person who is in love with someone understands how important this must be. Antonio seems to have a full proof plan to help his friend and pay back Shylock. Maybe this will give him the motivation to come forth about his love problems.