My dog is coughing more then usual...?

My Springer Spaniel, who is 12 years old, has been coughing alot within the last few days. on Friday she was coughing/ sounded like she was hacking up something in her throat, and by the time i went to bed that night she had coughed up a sliver of blood onto her paw. we couldnt take her in to her vet because they wernt seeing any of their regular patients unless it was emergency only. so my mom called and they said that they'd call us back around noon saturday, but never heard back from them. then on saturday she wasnt coughing as much but at some point later that day she coughed up a sliver pf blood again, so now we are trying to get ahold of the vet to get her in on tuesday. It still concerns me that she is doing this, and i was wondering what's going on with her. so if yall have any clue then let me know. id give more detail but this is all i know...