Your symptoms are concerning. While they could be related to nutrient insufficiencies or transitory discomfort while ketoadapting (ie low carb flu), it could also be a couple of serious medical issues. It may be worth seeing your doctor.
Having said that, if your diet doesn't contain either 1)organ meats or 2)supplements you are getting insufficient amounts of magnesium, several b vitamins, zinc and selenium.
When severe selenium deficiency is accompanied by severe overall malnutrition, symptoms can include weakness or pain in the muscles, discoloration of the hair or skin, and whitening of the fingernail beds.
Early signs of magnesium deficiency include loss of appetite, nausea, vomiting, fatigue, and weakness. As magnesium deficiency worsens, numbness, tingling, muscle contractions and cramps, seizures (sudden changes in behaviors caused by excessive electrical activity in the brain), personality changes, abnormal heart rhythms, and coronary spasms can occur [1,3-4]. Severe magnesium deficiency can result in low levels of calcium in the blood (hypocalcemia). Magnesium deficiency is also associated with low levels of potassium in the blood (hypokalemia) [1,19-20].
Thiamine deficiency (B1) - beriberi...wet and dry. dry affects the nervous system
Symptoms of dry beriberi include:
Loss of feeling (sensation) in hands and feet
Loss of muscle function or paralysis of the lower legs
Mental confusion/speech difficulties
The lack of variety food intake that some fall prey to, likely precipitates nutritional deficiences which then cause other problems. Optimally, you'll move towards including a greater variety of animal parts in your daily diet - until then, some supplementation is in order.
Chris Masterjohn writes on the issues of excessive muscle meat consumption:
I can't imagine a scenario in the EEA in which we didn't eat the whole animal, yet few in the paleo and primal communities have embraces "head-to-tail", "nose-to-tail" or "whole animal" eating. Relying on muscle meat only does not nutritional sufficiency make.
Where traditional diets are still eaten, and with the data available regarding traditional diets in the past, it's perfectly clear that the whole animal was eaten, often with a bias toward organs (brain, lungs, liver, kidney et al), glands (thymus, adrenals et al) and fat.
There is no risk* of eating whole animal but possibly significant risk if we don't.
*There is a tiny, truly miniscule issue with prion diseases (HT to whomever edited previously) :