Hi Yes, My Dog Has A Heart Mumar, That Moved

hi yes, my dog has a heart mumar, that moved up in stages about two months ago. 4 weeks ago she collapsed on the floor and howled in one continuous howl, I did not take her to the doctor, I did not have the money. Yesterday she did the same thing--except this time she did not faint like the first time. Is maybe the mumar getting worse or maybe her heart is stopping--I know I should go to doctors--but I am scared they might suggest I put her down and she is only 13 --it seems to soon