Implanon and pregnancy "feeling"

I know this question is asked a lot, but I'm currently going through some problems and would like to share them with you all, and maybe get some sound advice.

Hi I'm new to these forums, my name's Amy and I'm 26. I've had the Implanon implant in for about 2 1/2 years. I'm not in peak phsyical condition (I'm slightly overweight, UK size 16) for the last fortnight or so I've had a "sick" feeling, but haven't vomited as yet it's just dry wretching. I've also been feeling very fatigued and I've noticed that I have water retention, especially around my face and stomach. I haven't been doing anything differently, except not enjoying sex as much as I was a few weeks ago.

You can probably guess what my question is going to be so I'm just going to say it: Could I be experiencing the early stages of pregnancy due to the Implanon's effects wearing off because I'm slightly overweight?

I've had the "pregnancy" feeling that women say they get on Implanon a few times in the past. But lately they've been feeling a lot more real. I still have irregular periods, I finished one about 7 days ago.

I've also been thinking about taking a home pregnancy test but I'm not sure if it'd work due to the hormone that the implanon releases. So I've wondered if I could ask the doctor to take a blood test to make sure?

Has this happened to anyone else?