Help! Posts and Fonts completely messed up

Help Please!!!!

I am new to WP, and this type of program. I am beyond frustrated at this point, things keep getting messed up over and over again.

The posts were fine, then all of a sudden now all of the posts, except the first two are so small you cant even read them. The first two are fine.

At first I thought something was wrong with just a few posts, since page two was fine, so I deleted those few posts and then the posts on the other page moved forward and now they are all messed up now too.

Also, I deleted the stock photos in the header and added my own picture and the old ones are still there. I deleted them in the server ftp folder as instructed.......but it didnt work, they are still on the header.

Any help would be apprecaited! I am at the point of calling it quits, spent days and days trying to get this and its just not going well.