Everyone has their "signature" licks. What you feel is normal, everyone goes through it. I am faily new at the bass, but been playing the drums for 25+ yrs. When I feel i am at a stalemate, I usually break habits and create new ones. I find myself at some club and zone in on the drummer. I start feeling better right away by I realizing that I dont suck. If I happen to stumble on a good drummer, I just observe, and during a break tell the drummer how good his drums sound and how great he is. A little chat and We are teaching each other stuff we didnt know.
I was at a club where I saw a bassist that was so good, I felt bad for him because the rest of the band was awful. I went over to him and asked him about a bass line he did. He was so happy that someone recongized some thing he did and also commented that his drummer cant play anything except straight 4/4 rock. "this dude is slowing me down". He mentioned that its tough to find a good drummer.
I told him to give me a call if he wants to jam. He said 2 bass players in a group wont happen. I told him I played the drums, but wouldn't mind learning a few bass lines.
To make a long story short, we hooked up, me on drums playing some funk and odd time stuff and him playing anything I through at him. This is how I learned how to slap the right way, and how to slap pentatonic lines, hammer ons, slides, chord changes that work.
So get out there and listen to every bassist you can and try hooking up with them. Bounce Ideas off each other. One idea will get you out of that rut your in..
Good Luck