Have you downloaded anything thro cydia recently that after doing that caused issues.
Its a process of elimination.
Remove your most recent tweak/app download and check if that resolves the issue.
Also google for more info on possible known compatibility issues with the tweaks you have.
You can download apt backup via cydia to back up all your tweaks so if you have to do a restore you can then re download them.
Lucklily I've not had many compatibility issues via Cydia apart from a little lag via winter board !!