Take five of them!
Anything you can take is beneficial, but I would highly recommend getting the 5000 mcg. tabs and taking them three times a day until symptoms improve, and then two a day for life.
Yes, it is exciting to feel better after having that damn deficiency! I was grateful that I wasn't falling asleep everywhere anymore.
In your case, too much methylcobalamin is NOT harmful! Too little is. But it has to be methyl, not cyano. They do have injectable methyl. There is a chance of a reaction, because it's a drug, but you probably won't have one.
I'm so glad that you are having this taken care of. What a great relief!

Annie