Abnormal bleeding ! Frightened

So typically cycles range from 33-40 days. On CD 18 I started spotting and now 2 days of very heavy bleeding. Think it is way to early and to heavy for implantation bleeding?? Anyone else experienced this and found out what it could be? I have a doctors appointment tomorrow but worried wasting their time. Will add, I am on clomid. Any help to put my mind at rest would be great