I have large blood clots on my period? If I take aspirin, will that help the blood flow instead of make clots?

Blood clots. The reason you have blood clots during your period is different than what Aspirin does in your body. If you take daily Aspirin you might bleed more heavily.
No and need not. Blood clot formation occurs in other ways when it exits the vascular system and Aspirin will probably not change this. Nor is it necessary to change this. However I defer any further elaboration to someone with expertise in women's health.