10 days late of period and 2 negative pregnancy tests

Nicola
Hi guys
​Wonder if anyone can give me advice. I'm 10 days late of my period and have 2 pregnancy tests but came back negative. Took one when I was 2 days late and one when I was 8 days late. I've never been late before only when I was pregnant with my 1st baby. I'm usually 28 days cycle. Me and my husband have been having unprotected sex to concieve. I am very confused if I am or not. I haven't had a proper period since December. I did have spotting at beginning of February which was brown colour and lasted 3 days. Got constant cramping and headaches and feeling dizziness etc. don't know what to do! Any advice or help would be good!!
​Many thanks