Dropping "pas"

I only recently began speaking French again after (too) many years of neglect. I maintained my listening & reading skills, but not my oral. Thus, if anything, I would say by listening & oral have improved, while my oral reproduction has declined (e.g. greater passive vocab, smaller active vocab, etc). One particular mistake I think I've heard myself commit is inadvertently dropping "pas" in negative structures, yet retaining "ne", e.g. "je ne travaillais". I realise it's a very basic mistake, & one I would instantly recognise upon hearing another make it. Frankly, I can't understand why I'm doing this. The only potential explanation of which I can think is that, about a decade ago, I spent three years learning Spanish. I became pretty good in oral Spanish, & even to the extent that it briefly surpassed my French. Then, all of a sudden, I just stopped Spanish altogether (because life circumstances changed), & now I've almost entirely forgotten it — although my French has stuck (perhaps because I began learning it at a much younger age). Nonetheless, I wonder if somehow Spanish grammar has ousted my French grammar in this particular regard, where Spanish typically uses only one negating word, which adopts a frontal position. Any ideas ?