I'm afraid you'll have to delete everything and redo the post.
a) After you insert a captioned image, you must make sure the cursor is outside the caption before doing anything else or the captioned images will get messed up.
b) Apart from this, the arrangement you're looking for is impossible to create in the Visual editor: you need an HTML table.
Switch the editor to HTML and insert the images (pressing return twice after inserting each one). Then paste this (adding as many code lines as you need):
<tr><td>TEXT1 HERE</td><td>IMAGE1 CODE HERE</td></tr>
<tr><td>IMAGE2 CODE HERE</td><td>TEXT2 HERE</td></tr>
<tr><td>TEXT3 HERE</td><td>IMAGE3 CODE HERE</td></tr>
<tr><td>IMAGE4 CODE HERE</td><td>TEXT4 HERE</td></tr>
Cut and paste the image codes where I'm showing, add the texts where I'm showing.
The final result can be refined if necessary.