Your widgets do appear on your homepage at the very bottom below the posts. If you have been copying and pasting text from elsewhere without using either icon 5 or icon 6 in Row 2 of the visual editor, please see here http://en.support.wordpress.com/visual-editor/#pasting-text Typically this is caused by an open HTML tag in one of your posts and it sounds like your most recent post is the one that is creating this issue.
Go to Settings>Writing, tick the option "WordPress should correct invalidly nested XHTML automatically", click Save Changes, then edit the post (make any change such as adding then deleting a space or something) and click Update.
Posts > All Posts, change all your latest posts to Draft, click Update, change them back to Published, click Update again. (You can edit all of them at once: tick the square in front of their titles then select Edit from the Bulk Actions dropdown and click Apply.)