Spotting?

So my period was due a week ago and i have irregular periods but they are always from 35-38 days long. Well I thought i started 2 days ago (in the evening) since i stared bleeding, but that was only for a little bit. Then the next day i did not bleed, then i started bleeding again in the evening the following day. But today in the morning I was not bleeding again. Has this happened to anyone? I am TTC for my first baby. I did take a test about 3 days ago and it was negative should I wait to take another one? Thank you in advance.