B12 injections response

Started injecting 1500mcg hydroxocobalamin EOD on the 21st of August so far ive injected 3 times. First day i didnt feel much difference, second day i was better, more energy, woke up earlier than usual, head less foggy, more positive, happier, i felt pretty good for around 4 days, not always amazing but most of the day i was better than usual.

Since yesteday looks like I started falling again into fatigue, depression, head less clear, anxiety.

Does this indicate for sure that i am responding to b12 treatment and that i have a deficiency or could i just be high from all the b12 and other supplements?

Could this be a cofactor problem or there is no way of avoiding the end of the honeymoon period and the start of wake up symptoms?