I know it's the stock answer here on TB, but in your case I think that getting a few lessons from a good teacher, would be money well invested. A teacher can assess your level, then advise and direct you accordingly.
If you decide to go it alone, then learning scales, while it is important to know them, will only get you so far. IMO, and I am by no means an expert, the best way to go is learning about chords, chord tones, and their inversions. The latter especially, will get you thinking in a whole new way about playing. For example, not always starting on the root of a chord, can make it sound different. Below are links to some lessons that I have found helpful.
YouTube - Dave marks walking bass lessons
This one, while about walking bass lines, is good all round as it gets you thinking about inversions later in the series. I think there are nine lessons in all.
How to practice bass arpeggios | Scott's Bass Lessons
This one is from the site of a fellow TB'r