First question: do you have good ears ? If you can copy things really well, i guess yes.
What you can do in parrallel;
- Learn by ear any melody, solo from another instrument (Miles Davis trumpet solo from "so what" is a golden one to try on bass) : by this way you will get out of bassline state of mind and open what you play to other ways and licks. Plus, if you have to try to sound the closer you can from it: you will discover some ways of articulate things that are different from bass playing, and will make you work on different ways of making music breathe.
- Take a bassline you know; set up a drum machine on different styles of music and try to adapt the line you know in another music style. This exercise is really fun sometimes. For example If you'are in Metal, try to play your favorite tune in Latin flavor, tango, straight swing, etc.. It will ead your brain and ears to adapt to a new situation where you will have to focus on dynamics, and how to adapt a bassline to make it work in any style.
- Take a tune you love and which you know the bassline: learn all other instruments parts on the bass. Simulate drums with slap, play the singing melody, etc.. Same benefit than first advice, plus you'll have a wider view of the tune by experience it.
- learn pentatonic scale and switch in guitarist mode in your head: try to make solos over blues tunes using these pentatonic scale and mixing notes in all possible ways with an simple goal: to sound "in tune" with the tune you're soloing over, but without thinkin in licks or already known melodic gimmicks. Don't expect to be great, but just sound the best you can with these notes. (during this exercise, give holidays to yor internal judge

)
Pentatonic solos will help you to take confidence about trying to improvese things. And little by little, all you already know will add some flavour in your pentatonic, but without thinking of it, like your inner vocabulary. Cause all you have done in 25 years has built some phrases, some note sequences that are in you, and that can be used as words in a new phrase you want to say. So once you will have crushed your fear to try, little by little these insluences will get out and enrich your pentatonic first solos.
Then, when you'll have a little more confidence, get out to jam and try to improvise with other musicians.