lansoprazole and acidosis? rare reaction

Hi all.
I was prescribed these by my doctor a little while back for the recommended course of time (under 6 weeks/one box), in the beginning they worked alright, not the same as rennies with immediate neutralization of stomach acid but more of a PH control. Hadn’t taken them for weeks, took one hours earlier now I am having some odd ‘reaction’ where it feels like there is excess acid in my blood.

First off obviously I won’t be taking more, but really now I need to know what to do about this or if it is some emergency, hope I’ll get a quick response here if not it’s 111.

Apparently this is a very rare side effect.

Should I drink water, take electrolytes, not do that or what. How could this have happened?