sore anus

I was having a "play" with myself 3 days ago, and inserted a toy in my ass. Everything seemed ok at the time, but around 8 hours after I started to get a pressure I'm my anus and a mild stomach cramp. I then had a little diarrhoea. Since then the pressure in my anus hasn't gone, even when I go to the toilet it comes back 30 mins later. Its not sore, it's just uncomfortable. It doesn't seem to bad when I wake up in the morning, just as the day goes on.

Also feel I'm a bit more gaseous than usual.

Anybody else experienced this?

Most likely your anus is bruised and your brain has become confused about whether it is clogged up with shit or not due to the new sensory pressures introduced by the bruising. If I was you, I'd go to a doctor immediately, as things are bound to only get worse.