It's impossible to describe what's happening without using a few graphic descriptions. It's a genuine question, so no need to feel awkward.
What's happening is that you are probably losing roughly the same amount of blood as you usually do, but it's doing what lots of women call 'flooding', in that it sometimes flows out suddenly and therefore feels heavier. Overall, you may still lose roughly the same amount of blood, or, more correctly menses (a mixture of blood and cell debris), but you may be heavier for a day or two and then the flow can be much lighter. But not necessarily to the extent that your period is shorter.
If over a few periods you find you seem to be consistently bleeding more heavily, do get this checked out by a medical professional.