JetPack Plugin Update causing a Problem

When I updated JetPack a few days ago, I started having problems.

This is what is appearing on my homepage:
Deprecated: Assigning the return value of new by reference is deprecated in /home/content/47/9795247/html/wp-content/plugins/jetpack/jetpack.php on line 3161

If I refresh, I can get to the actual homepage.

On my admin/dashboard page I get this message:
Deprecated: Assigning the return value of new by reference is deprecated in /home/content/47/9795247/html/wp-content/plugins/jetpack/jetpack.php on line 3161

Warning: session_start() [function.session-start]: Cannot send session cookie – headers already sent by (output started at /home/content/47/9795247/html/wp-content/plugins/jetpack/jetpack.php:3161) in /home/content/47/9795247/html/wp-content/plugins/contact-form-plugin/contact_form.php on line 885

Warning: session_start() [function.session-start]: Cannot send session cache limiter – headers already sent (output started at /home/content/47/9795247/html/wp-content/plugins/jetpack/jetpack.php:3161) in /home/content/47/9795247/html/wp-content/plugins/contact-form-plugin/contact_form.php on line 885

Warning: Cannot modify header information – headers already sent by (output started at /home/content/47/9795247/html/wp-content/plugins/jetpack/jetpack.php:3161) in /home/content/47/9795247/html/wp-includes/pluggable.php on line 881

If I refresh, I can see the actual page and I just have a message along the top.

I tried to deactivate and reactive JetPack and my other plugins. When JetPack is deactivated, the problem disappears. I’ve considered uninstalling JetPack, but my Blog e-mail subscription runs through JetPack and as far as I can tell, there is no way to manually re-enter my subscribers. I’ve also considered reverting to an earlier version of JetPack, but I don’t know how to do that or what it would do to my list of subscribers.

Any advice you can offer would be appreciated. I’m very new to this and I don’t know anything about coding, so the more explanation you can offer the better.
Thank you very much!

The website is: pghntma.com