It sounds like either (a) the cartridge's suspension has worn out, or (b) you're applying more tracking force than you think. In either event, the cantilever could collapse under load as you described. Do you have a (reliable) VTF scale or are you just using the dial on the tonearm? Those are notoriously inaccurate on Regas.
If the cartridge is riding low, VTA/SRA will be lower than they should be. Excessive VTF and low SRA can both cause excessive/thick/muddy bass and/or attenuated highs.
1. Reduce anti-skate to zero (for setup purposes).
2. Measure your VTF with a decent scale and adjust if necessary.
3. Reset anti-skating to NOT MORE THAN 1/3 of VTF.
4. Observe results when playing a (non-valuable) LP.
If the symptoms persist, have the cartridge checked by a qualified technician. Odds are it's shot.
The music sounds good except excessive base and lack of highs.That doesn't sound very "good" to me. Just because a cartridge reproduces something resembling music doesn't mean it sounds good.
If the cartridge is riding low, VTA/SRA will be lower than they should be. Excessive VTF and low SRA can both cause excessive/thick/muddy bass and/or attenuated highs.
1. Reduce anti-skate to zero (for setup purposes).
2. Measure your VTF with a decent scale and adjust if necessary.
3. Reset anti-skating to NOT MORE THAN 1/3 of VTF.
4. Observe results when playing a (non-valuable) LP.
If the symptoms persist, have the cartridge checked by a qualified technician. Odds are it's shot.