Heavy watery period!

Warning TMI Ok so I usually have thick dark red blood and some clots of blood for my period. I took pregnancy test 3 and 2 days before AF and both were BFN! I was right on time with my period which im usually 2-3 days late. My flow is extremely watery, thin and very heavy. I am constantly changing in 30 mins to an hour. It is bright red but also very watery just dripping everywhere.... sorry tmi I am having to wear a tampon and pad. Also had to go home to change :( please help has anyone else experienced this?!?