My son has turned into a devil (Terrible Two's)

[Romibanana]

Help! My DS is 2 years & 3 months old.
He hits random people when we walk to school, he hits his sister & myself at home (not all the time but every day).
He keeps running off. Yesterday he ran from my mom-in-law (who had him for the day) in the shops. She was absolutely petrified, poor thing. The whole shop looked for him until some old lady found him 'outside' sitting in Thomas the Tank engine... :(. He runs so fast!!!!
Also, we thought we potty trained him before Xmas, he was nicely asking 'Mummy - I need a wee'. I thought how awesome, that was easy. We are back at soiling pants, so back in the pants-nappy... :(
He has always been such a darling, talking really well and really early, very aware, but my god, he can't be trusted right now...
He is absolutely adorable, and I think he knows that. So we are trying to do bit of tough loving with him now he's turned! Grrr

My DD went through this just before she turned two and it was awful for a few months but she gradually improved..She still has her moments though. She's 2.5 now.

With the running off, I always take her buggy out with us. (We walk everywhere as I can't drive). I will let her walk and run anywhere that is safe - open spaces, away from traffic etc, and I let her walk down quiet residential streets. But the second she does a runner I say to her "You have one more chance but if you don't walk with mummy you're going in the buggy". She used to run off again and I'd put her straight in (she would kick and scream). This has worked really well and she doesn't run off now and is much better about things like not running up people's drives or climbing on their walls when I say "that's someone elses house you can't go there", she also makes much less of a fuss about being put in her buggy. Though I only let her walk in a supermarket or shop now if her dad or someone else is with me otherwise it's too hard to control her if she does run off.

She hasn't been so bad with hitting. She did (and still does occasionally) hit me but nobody else. When she hit me I'd pretend to be sad and say that she's hurt mummy and it isn't nice/kind to hit people. She is doing it much less frequently now and really improved. Although that could be her age as well.

I have no advice on potty training as the only thing she has ever used her potty as is a stepping stool to try and reach things and climb on things that she shouldn't be climbing on! She's still in nappies now.