Suddenly flooded with hundreds of spam newsletter subscriptions

Suddenly flooded with hundreds of spam newsletter subscriptions

This happened overnight. There were 350 in my box this morning. They are mostly newsletter subscriptions. Many are foreign. I don't know if I've been hacked. I don't know what to do about it. I thought it could've been a faulty spam filter at Zoho but my husband's email isn't seeing the same issue and we both have Zoho Mail. Is this a spoofing and I shouldn't worry or a hacking or what? None have come in over the last 45 minutes so maybe it's stopped. But I'm a little freaked out. And it's hard to even SEE if there are legitimate emails with so much trash. Thanks.