Fear comes from a lack of knowledge
I used to fly bank checks in crappy planes, single engine etc. all wx.
may I suggest.
one...fly an IFR flight with nice weather and a nice local area that you are familiar with.
next, fly the same flight IMC (also IFR for you english guys) with lots of weather briefing and within the capabilities of you r plane.
then do it again.
ok for baby steps...but remember anything CAN happen on a nice day or a bad day. you are responsible...you have to know what to do if you are IMC and your engine quits.
you have to have ideas and the imagination, yes imagination to handle things...flying is done with the imagination so try thinking through a flight.
eventually you will get used to it...even imc at night.
good luck...