Reccommendation for a latex mattress topper to help with my pain issues caused by memory foam mattress

I am a petite female 5'3" 125 lbs, curvy/pear shaped. I am currently seeking chiropractic care for back/hip issues.I previously owned a very plush Beautyrest pillowtop mattress (hybrid of foam/coils) which developed body impressions within the first year. Just four years later it had dips/indentations 3-4" deep. I've since replaced that mattress and purchased a Nectar Lush foam mattress (rated medium in firmness) in late November. Three months later I still have not adjusted. I now wake up several times throughout the night due to discomfort, also waking up in the morning feeling stiff and in pain - aches/soreness in lower back and strange tingle/tightness sensation down my legs into my heels/feet which improves as the day goes on. I believe since sleeping on this mattress I've developed sciatica nerve pain and other unexplained discomfort throughout my entire body. I am a back & side sleeper, however, I've noticed when sleeping on my side it makes my hip and lower back pain worse. I feel like my hips/pelvis may be tilting forward and/or leaning backwards in my sleep, creating a "twist"/strain on my hips and spine. I'm trying to determine if this mattress is too firm for me, perhaps I'm not sinking enough into the layers to support me properly or perhaps it's not quite supportive enough and my hips are sinking in too deep compared to the rest of my body causing me to fall out of alignment? I'm considering adding a latex topper to soften my mattress in hopes it might help, but I am having trouble deciding between 2" or 3" thickness, AND soft talalay or dunlop? I want to add more plush softness of comfort also keeping in mind I need to have enough support to keep my spine properly aligned. I've spent countless hours researching, reading reviews and forums to help solve this problem. Your expert advice and/or recommendation would be greatly appreciated?