Venlafaxine and cannabis.

Hi. I have been vaping a very small (pea size) amount of cannabis every night for over 10 years to stop my restless leg syndrome and let me sleep. For the last two years, I have also been taking prescribed venlafaxine for depression (previously I was on fluoxetine). Over about the same period, I have really struggled with extreme fatigue - especially in the morning.

Does anyone know if there is a known link for both these drugs to cause fatigue? Thanks.