I didn't read the whole thread so not sure wether you mean 18% of your trading account, your liquid net worth or your net worth.
If the first case I can relate as I swing trade manually a volatile strategy and I saw my account go down this kind of percentage already a couple of times (possibly more than a couple ).
It hurt every time financially and psychologically but have been fortunate enough to get back to positive in few weeks or months.
Usually I reduce size enough to use a similar margin percentage of the account, but also add funds if I feel the positions are not big enough.
Anyway good luck, drawdowns are tough times to go through.
18% or total net worth, trading gave me my entire net worth, which is all cash.