Today i recived a lot of bounced back emails as if they were originally sent from my account

Is it possible to tell by the header if it's my mail server compromised and some one sending out spam using my mail server?

I do have link@mspiercing.com account and my server's name is mail.mspiercing.com

Here is the header from the email (Bounced back email had orignal email as an attachment)

Thanks.

Return-Path: <link@mspiercing.com>
Received: from hedy-edc68d57b3 ([123.6.229.63])
by mail.mclogi.com.sg (8.13.7/8.12.7) with ESMTP id m980JZTX027431
for <cryamlloyd.com.sgshimashima@mclogi.com.sg>; Wed, 8 Oct 2008 08:19:41 +0800
Received: from [123.6.229.63] by mail.mspiercing.com; Wed, 8 Oct 2008 08:19:37 +0800
From: =?koi8-r?B?IvbP0sEg6MnTwc0i?= <link@mspiercing.com>
To: <cryamlloyd.com.sgshimashima@mclogi.com.sg>
Subject: =?koi8-r?B?78LV3sHA3cHRINPJ09TFzcEg0M8gRVhDRUwgMjAwNw==?=
Date: Wed, 8 Oct 2008 08:19:37 +0800
Message-ID: <01c9291e$9a39b280$3fe5067b@link>
MIME-Version: 1.0
Content-Type: multipart/alternative;
boundary="----=_NextPart_000_000E_01C9291E.9A39B280"
X-Priority: 3 (Normal)
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0)
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869
Importance: Normal
X-Spam-Score: 3.738 () FORGED_MUA_OIMO,HTML_FONT_BIG,HTML_MESSAGE,MIME_CHARSET_FARAWAY,RAZOR2_CF_RANGE_51_100,RAZOR2_CF_RANGE_E4_51_100,RAZOR2_CHECK
X-Spam-Status: No
X-Scanned-By: MIMEDefang 2.57 on 203.95.72.122

This is a multi-part message in MIME format.