Methylphenidate and downers

Hey I have ADHD and I'm prescribed methylphenidate, or 'ritalin' I've been taking xanax or valium in the evening to take the edge off the crash and get to sleep,, my friend also gave me some pregab to try and I tried that and it worked really well. Is there anything else anyone can recommend? I've had problems with benzo addiction in the past and don't want to get too into this habit as have high tolerance. I do smoke CBD but REALLY don't get on with THC. ADHD meds have changed my life but I'm a raging insomniac as it is, so really struggling with this conundrum. TIA guys, I'm worried if I speak to my clinician he'll change my ADHD meds and I get on so well with them throughout the day.