Hi Rachy -
I've been lurking for a while but upon reading your post I am compelled to write. I am so sorry to read of your current battle with the cramps and spasms, this is quite familiar to me and I feel for your pain.
I had similar to what you are describing on an intermittent basis for several years progressing to a nightly basis for well over a year. Several times every night, both feet, ankles and legs spasming and contorting in waves between which I could find moments of sleep for perhaps 40 or 50 minutes at a shot. After particularly bad episodes I had great difficulty walking. (You may wish to Google "myoclonus+multiple+sclerosis" for some interesting reading.) I had an idiot of a GP who refused to acknowledge the severity of this progression, or my ongoing reports of other neuro symptoms over many years, and kept suggesting sleep medication (Ambien, Soma, etc.) or the ubiquitous "anti-depressants"... but that's another story.... and alas, a story too familiar to many during their long slog to diagnosis.
Ultimately back in February I had a whopper episode and horrified friends witnessing this called 911, and it took a new consulting physician (a podiatrist!) about 42 seconds to get a brief history from me and surmise it might be MS. And then the new adventure began....
I wanted to share that I started with Baclofen, and the improvement was immediate. It was my first night of uninterrupted sleep in about 8 years. I have a very low threshhold to any medication so I only needed 20mg at night. I also worked with my Neurologist and his in-house Physical Therapist and Nutritionist and began supplementing with --yup -- magnesium, potassium, the B's, D3, among others. I have also taken up daily core-building exercises and Yoga under the guidance of a personal trainer knowledgeable in my neuro/muscular issues. I weaned off (important - don't suddenly stop) the Baclofen after about 45 days -- it gave me some seriously dry mouth and I wanted to know if my new nutrition/supplement/exercise regimen would hold things at bay.
I'm delirious to report that I have not had a single episode of the excruciating foot/ankle/leg spasms and cramping and significant mobility losses since that last 911 whopper in mid-February. I now sleep like a rock every night. The various typical sensory weirdnesses and some loss of functionality in one leg that I've had for many years have improved maybe 30%. My neurologist says "Keep doing what you're doing and I'll see you next year."
In summary, what worked for me was (1) getting referred to a Neurologist who listened (oh blessed day!), (2) Baclofen (temporary), (3) ongoing nutritional/vitamin supplementation (with emphasis on magnesium/potassium/B's) and (4) strength- and core-building/Yoga. Given that I battled with intermittent cramping and spasms and mobility issues for many years, and with daily multiple attacks for over a year, I think it unlikely that this was something that spontaneously remitted. Between the Baclofen, which gave me an immediate break from the pain and the resulting sleep deprivation and exhaustion, and the nutritional/vitamin/exercise aspects that incrementally rebuilt my physical reserves and stamina, the improvement in my health -- and the quality of my life - is incalculable. I want to emphasize that I always imagined Yoga to be about as exciting as watching paint dry -- I'm a Type A personality and in times past you couldn't pay me to try it -- but now I deeply believe that the benefits and results specific to my Yoga sessions are ginormous -- and go figure, I find that I actually loooove it. My hope is that perhaps something in my experience will be of immediate and long-term help to you as well.