Is this even worth fixing or selling or should I just throw it out?
Some pieces are not worth the effort or cost to fix.
There comes a point when you must be willing to let go of things you have enjoyed wearing. This point arrives sooner for a lot of costume jewellery than jewellery made from precious metals, but it does happen for both types.
It is time to let go when the only thing holding your jewellery together is glue and it has been fixed that way multiple times.
Listen to your jeweller. If they tell you they can fix something but it will break again you should be asking if there is something else that could be done to fix it, or if it should just be put to rest. Honest jewellers will advise against repairs they know will just come back with the same problem repeatedly.
If you find your jewellery is breaking often, you may want to invest in higher quality pieces. Higher quality does not have to mean more expensive materials or stones, just that it is made with more care for the longevity of the piece to withstand more frequent wear. Do not be fooled into thinking luxury brands are better because they are more expensive. Quality is not dictated by price, but rather it is a reflection of how well the item is crafted.
Glue rarely says well made!
’20 Tips on maintaining our Jewellery’, Gillian E. Batcher, 2013