I'm going to chime in with Rocksmith too. That's kept me playing when I've not had a gig to practise for and is a ton of fun.
I've been playing for about 25 years and I'm still crap. That's my problem. If you decide to stick with it, here's some tips:
1) Stop looking at youtube heroes.
There's a million of them out there, kids with nothing else to do but play for 12 hours a day and they put stuff on youtube and annihilate almost everyone's skillset despite the fact that they're 16. Even then you'll still get some commenter saying they suck. Ignore these people, they have nothing else in their life and it is unrealistic for someone with any kind of life to reach that level.
2) Join a band
Others have said it but nothing gets you better than bouncing off other people and NEEDING to get better. Worried you suck? Who cares? There's a band out you that sucks harder than you do, go find them.
3) Technical proficiency isn't actually that important
As a bass player doing stupid runs is not your focus, your focus is to keep the band together, create the groove and play what's right. That's one thing I think is unique about bass in your standard 4 piece is you're the only ensemble instrument, the rest are solo-tastic. Musical understanding > Technical proficiency.
4) You have bad days/weeks/months
I have days where I play with something and feel like one of the great 70s disco bassists, and then I have days where my fingers have turned into dicks and flop against the strings uselessly. The whole point of practising in my eyes is so if you have dick fingers in the middle of a gig it doesn't destroy everything. At the end of the day the main thing is knowing this happens, so if you practise one day and it's terrible know that today you've just got dick fingers and there you go.