I have a really large form, what if user stops filling in form half way...

What if a user that is filling out my form gets bored after just entering the contact info...is there a way to capture the information they added to the form before they abandoned it?

Specifically, if they add contact info, but never fill out the remaining form questions, can I retain the first 5 form entries even if they never press the "Send Now" button. 

One thing I would recommend is first for you to Enable the Autosave and Continue ability.

The second thing that may be a good idea to consider is if you at least want to first make sure you have captured the contact info then it might be better if you were to separate that into it's own form and place it in front of the rest of the form which would redirect to your second after submitting the first time to gather further information in example. Or if you wanted to get even fancier with it you could use the Text Field to embed it.