I agree with John. There is no point in having a drone if your not going to use it and there is no point in using it if you dont trust it. If you do nothing else in the next week simply keep flying the drone away and hitting the RTH. As stated before ensure the RTH height settings will clear any buildings, trees etc by a good distance.
A few of things I should mention.
1. Dont fly from your back garden, apart from the legal stuff, unless you have a very big garden it could come to land next door. There is a precision landing setting but lets just stick to basic Return To Home for the min. 3 times out of 5 it will land 12-30 feet away from where it took off. As I said not every time but depending on circumstances, GPS, Compass etc it
could go a little off landing pad so to speak. So fly in an open safe space till you know your and the drones limitations. More than once I have nearly landed it in a field hedge. Miles clear in front but I had a tree hedge behind.
2. When you press the RTH and say the drone is 40 feet in front of you do NOT expect it to come straight back to you. I did when I had my first drone and nearly had a brown trouser moment when it suddenly shot up into the air by 100 feet. To avoid obstacles that may be between you and the drone it firstly goes straight up to its Return To Home height. It then moves along and down. A sort of n shape in the sky.
3. Learn how to
cancel the RTH. Its easy just push the cancel button on the left middle of the screen. Again just practice that a few times. Better to find out how to do it now than when you really need it. (like my BTM above

) It will simply stop and hover.
4. Even in RTH mode you still have control via the sticks if you need it.
5. Relax. This is supposed to be a fun hobby. Perhaps you could find a flying buddy who lives nearby to help until your confidence builds up.
Hope this has been of help.
