Advice needed please

Stacey

The last two months my periods have been shorter than usual. I get all the symptoms as I usually would and it come on time. HOWEVER, I could be sat down and nothing then stand up and it suddenly gushes, then have red bleeding for a couple hours then just some brown spotting for the next couple of days. Is this normal? It’s really freaking me out and I already have anxiety so don’t need this on top.