If you changed more than your meta tags, then it could be other things have affected your rankings.

You need to be scientific about changes to your site and make notes. Try to not change too many things at once or you cannot be sure what changes caused what affect.

Since you don't list all the changes you made, no one can advise you. You should have a unique title tag, and unique meta description tag,and a unique keywords meta tag for each page. If you use keyword phrases that have been researched, use as many keyword phrases as possible, AND make all your text good English usage, then you should have good results.