Too much spam in inbox

For the past week or two, my inbox has been filled with spam. The spam filters still pick up some of it, but I've been having to manually delete way too many spam emails from my inbox. I haven't signed up for any websites that would result in this, and I was just wondering if there was anything that could be done to stop this? I've never had any problems with this before, until a couple weeks ago. Thanks in advance!