I am having memory loss, I am confused I am unable to find the right words for things, I am scared I am stress?

I loss concentration, conversations sometimes feel like I hear it in another language...my dr has ored a b12 profile my mri brain scan is fine so would not that rule out Alzeimers???? Can a lack of b12 do all this??? and will I get completly better if my b12 is fixed...I can only see my dr. every 3 mos. So my appt is in july but in the meantime I get scared ..yes I have put myself on b12 following the direction and my bloodwork will be done late june and yes I will tell the dr. I started b12 on my own and at what date but I thought I would see a change by now Its been 6weeks Please give advice I need info in laymans terms all the site are overwhelmong Please help