I found this information on symptoms relating to vit b-12 deficiency.I know your questions relates to symptoms you are getting from RECIEVING the b-12 shots .But I find it ironic that the symptoms you list are associated to the deficiency .There are some suggestions for foods that could help with your def and you could also try adding the folic acid at the time of your b-12 shots.
Recent studies have shown that there is a definite benefit to be gained by giving vitamin B12 to patients suffering from depression, fatigue and mental illnesses of other kinds. Even a slight deficiency of B12 is found to produce marked symptoms. See Folic Acid below.
Vitamin B12 is found mostly in meat and animal proteins. B12 is stored in the liver. A deficiency can lead to symptoms such as dementia, changing moods, irritability, paranoia, mania, and confusion.
Dosage: Take 300 to 500 micrograms twice a day.Also low levels of folic acid have been noted in depressed patients. In studies of depressed patients, 31-35% have been shown to be deficient in folic acid. In elderly patients, this percentage may even be higher. Studies have found that, among elderly patients admitted to a psychiatric ward, the number of patients with folic acid deficiency ranges from 35% to 92.6%. Depression is the most common symptom of a folic acid deficiency. Other symptoms of folic acid deficiency are: fatigue, apathy, and dementia.
Folic acid, vitamin B12, and a form of the amino acid methionine known as SAM function as "methyl donors." to important brain compounds, including neurotransmitters. Without the methyl group, the neurotransmitter cannot perform its function. SAM is the major methyl donor in the body. The antidepressant effects of folic acid appear to be a result of raising brain SAM content.
Supplementing the diet with folic acid, vitamin C, and vitamin B12 was found to increase BH4 levels in the body. BH4 (tetrahydrobiopterin) is essential in the manufacture of neurotransmitters such as serotonin and dopamine from their corresponding amino acids. Patients with recurrent depression have been shown to have reduced BH4 synthesis.
Folic acid supplementation and the promotion of methylation reactions increase serotonin levels. Elevation of serotonin levels is responsible for much of the antidepressive effects of folic acid and vitamin B12.
Drugs such as aspirin, barbiturates, anticonvulsants, and oral contraceptives can inhibit the absorption of folic acid in the body. Good sources of folate include pinto beans, navy beans, asparagus, spinach, broccoli, okra and brussels sprouts.
Dosage: Typically, the dosages of folic acid in the antidepressant clinical studies have been very high: 15 mg to 50 mg. High-dose folic acid therapy is safe ( except in patients with epilepsy) and has been shown to be as effective as antidepressant drugs.
A dosage of 800 mcg of folic acid and 800 mcg of vitamin B12 should be sufficient to prevent deficiencies in most circumstances. Folic acid supplementation should always be accompanied by vitamin B12 supplementation to prevent folic acid from masking a vitamin B12 deficiency.
I hope this helps you in some way ,my thoughts and prayers are with you ,please let us know how you are doing and if there is anything I or anyone else can do to help you