Can anyone help me...?

My period was a week late (last month) and finally arrived two weeks ago. Yesterday, I started what I thought was my period, by yesterday afternoon it didn’t come to much and this morning I have got up and there is nothing. I did have light cramps most of the day but, nothing like when I get my usual period. Could this be implantation bleeding or something more sinister, like early menopause? (I’m only 30!!) Hubby and I last had unprotected sex on Saturday (he’s working away). I haven’t taken or done anything different. I’m feeling worried, any advice would be greatly appreciated.