I really think you should consider the ad's. Can you really carry on feeling like you do now? Life is too short to be this sad, so surely they are worth a try? I know you have one negative experience of them but there are plenty of people on here who swear by them, me included.
Do you want to lend the money? If you havent got it and you dont want to then dont. It sounds like you have done a lot for your family and you need to put yourself first.
What job does your dp have? does he have any kind of health cover or employee assistance that also covers you? you may be able to get some counselling through that route.
I really hope things get better for you.