Hi Jennie, sounds like you are doing well for only a few weeks practise. The chord you are talking about is called an E shaped barre chord as it is based on the shape of an E chord. When you play this chord with the barre at the first fret you get the F chord that you are talking about. In the video you will see that skinnybloke also covers these types of chords from about the 55 second point.
The good news is that everyone who has ever picked up a guitar has struggled with barre chords and many never master them. Constant practise is the only way to get to grips with them. You will probably find it easier to start playing them further up the fretboard as the closer you get to the nut the more difficult they are.
You can read more about them
here and
here.
The 4 string F chord that you can play is fine to use until you can get more practise on barre chords.