What Causes Constant Vaginal Bleeding With Clots?

hi just a query on almost constant vaginal bleeding. Ive been having my periods as normal usually lasting 4-5 days and then they stop but usually within a week im bleeding again and this can last for anything between 7-15 days and this has been going on for at least 6 months. More often than not this mid month bleed contains a lot of clots some quite big, if you could give me some idea of what might be going on i would appreciate that, im also waiting for an appointment to be sent to me for a scan. Im not sure if this could be connected but i also have a small lump on my left labia for more than a year and has been there for over a year.