Sorry to hear what you're having to deal with at the moment tango, as MB has already said, all the stress from the different things you have going off will be feeding both your FM and psoriasis. Found this linky, apologies if it repeats things that you have already come across
http://www.nhs.uk/Conditions/Psoriasis/ ... tment.aspx. Depending on what treatment you've already had, might it be worth seeing what else could be available to help you with it, as well as other things that might help you with your FM.
Getting people to try and understand what it is like to live with FM can be really difficult and frustrating. The majority of people struggle to understand because there isn't anything they have experienced that can be used to compare against our explanations. The others either don't want to know or can't be bothered to try and understand anything about it. For your parents, you could try showing them this
viewtopic.php?f=2&t=4732 Lots of people have said it has really helped exolain things, so it may be worth a try.
WRT your son, trying to arrange contact is difficult at the best of times, throw in an illness and it's off into another dimension

Sadly, it's something that can be used against you by your ex. Have you supplied any detailed info about your conditions from credible sources?? And maybe something from your GP and/or other medical people you have seen could help with your side of things

Not sure what else to suggest at the moment, ran out of steam a bit too early
There's always plenty of support on here, and we will try to help you with things. Even if there isn't an answer, just knowing that there is someone there to offer a

can help s well.