serious e-mail problems

I have several sendmail actions set up in my form scripts. Everything was working fine as of yesterday. Now, Half the time the mail does not appear in my mailbox. And sometimes, even the wrong script is run (one mail message for one script is sent instead of the one that should've been ran). I don't know what the problem is, but I can't use my database if the sendmail functions aren't working. Any ideas???? please help!