overdue?

Hi,

I’ve never really thought about "when to test for pregnancy?" since I already have a big daughter who is 6 years old, and I only found out about this one at 13 weeks. I had my period for 3 months (irregular cycle).
(I started finding it strange that I suddenly couldn't smell certain scents anymore, cigarettes and alcohol).
Now we are trying for a "little one", since November 25, 2015. Is it possible that I am already pregnant (until March IUD - from March to November Yasmin pill)?

I should normally menstruate in the first week of each month, sometimes on the last 2 days of the previous month, but always at the beginning of the month. Now it's already the 10th, and still nothing.
Last week I felt nauseous and lately I've had some heartburn, and sometimes the feeling that I need to vomit. This feeling is not just in the morning but also during the day, e.g.: when I have to bend over (I work in a store). I don't really think about my most fertile period and when to have sex, can and fits, to put it crudely. : )

I have already done an online test several times on different websites, these would indicate that I am pregnant, although I also know that this is not always accurate.

Because I had my period in April at the beginning of the month, then it stopped and around the 14th or 15th I suddenly had a little bleeding, but more brownish (could be implantation bleeding?), I would do a pregnancy test next Sunday.
I also have a lot of white discharge in the last 2 weeks, and regularly there were mucus plugs in it.

If I google my symptoms, I always end up with pregnancy.

If I test on Sunday, is the timing good or too early?

Thank you.

Little squeaks. x