Problem with Pubmed/online searching

I don’t know what is going on, but I have always been able to search pubmed from the main window in Endnote, and any references I found were automatically put into the library.

Now, I have to go into the “online” tab and the references I pull up don’t go into my library and I can’t insert them into my document.

Help! I’m on a very tight deadline.

there are two modes. You may want to try the Integrated Library & online search mode - although then you do need to be careful about the specificity of your searches and you should have the discard duplicates setting on in your preferences.  

See this youtube video 

The below is copied from 

Local Library Mode
This mode displays automatic groups, custom groups, and smart groups, but not Online
Groups. This mode keeps you from inadvertently downloading references found during an
online search into your currently open library. This is the default mode.
Online Search Mode
In this mode, only the online search groups are available. When you download
references from an online database, the references are stored in a temporary library
until you save them to a permanent library. You can then review the references without
affecting your local library.
Integrated Library & Online Search Mode
In this mode, all local library commands and groups are available. When you download
references from an online database, EndNote saves them to a group under the Online
Search group set and to your open library.
If you decide that you do not want to keep the retrieved references, select them, and then
move them to the Trash folder.
Note: We recommend that you use Online Search Mode if you do not want the references
downloaded to the All References group. Searching a Database

My problem is I always used the integrated library mode because the online search mode does not work. It searches for ages, and does not return any result. Why is that?

sounds strange.  I would check with tech support, as that is not my experience.