Harryjoesmum, welcome, you are not crashing at all, we like to give a hard time welcome all newcomers. Ignore the talk of meet-ups, it's all a show.
As for your sleep issues, I agree with SOH when she says that separation anxiety is a major 'issue' at this age. They are just learning that you and they are seperate beings and that scares them a great deal. Also falling asleep is something they have to learn to do themselves, some cruel mummies like me, help them to learn how to fall asleep at a very early age by letting them cry it out. However even I don't believe that at this age, a child should learn to fall asleep by being left to cry for long amounts of time. Can your ds fall asleep by himself? Does he go to bed on his own or by being rocked/pushed etc? What about daytime naps does he go down to sleep then with no problems?
First rule out anything that may cause your ds to wake as SOH suggests. He has now developed a habit of falling asleep with you in your bed and it will be difficult for him to break it unless he re-learns how to fall asleep on his own, but being used to you coming when he wakes and then falling asleep with you by his side means he feels safe and secure. I would suggest (and this takes time and commitment and a few tedious and potentially long nights for you) that when he wakes, you reassure him, pat on the back, with the light off, tell him its night time and time to sleep. Then stand over him and not touch him but reassure through words and sounds, without picking him up. He may cry quite a bit but after a wee while should drop off happily knowing you are there. Each night you do the reassuring for a little less time, he will still cry for a bit, but should learn to settle himself, until, hopefully he is happy again settling himself without you there.
Fwiw I have been blessed with 3 exceptionally good sleepers, but even my ds who is the same age as yours cries out in his sleep, without really waking. If I go in, give a quick reassurance and a pat he settles back down without really waking up.
Sorry for the essay, hope this helps a bit. Do let us know how you get on.