Am I getting pregnant or what?

Hi everyone.. Sorry, I've been reading a lot.

I'll introduce myself. My name is Bella and I'm 23.

I know this topic comes up often, but I'm in a situation where I don't understand my body anymore.

Here's the deal:
I was on the pill for about 2 years (desogestrel - a very light pill). I stopped taking it on Feb 4th this year. Since then, I've had a regular 28-day cycle (including this month).

I've had unprotected sex with my boyfriend, but we used withdrawal. Yeah, I know it's not foolproof...

Meanwhile, I've been feeling really weird for about 3 weeks. What I mean: nausea, itchy nipples, lower back pain, stomach cramps, gurgling intestines, bloated (even right after going to the toilet, I'm bloated again almost immediately), sometimes disgusted by certain foods, but also regularly hungry, tired but sleeping enough (8-9 hours/day).

I've taken a few pregnancy tests and they're all negative. Didn't really expect anything else since I've had my period..

But I read that (my doctor told me too) you CAN sometimes (!!) have your period and still be pregnant.

So what do you think.. Am I just experiencing post-pill symptoms (which I find weird since I've had a regular 28-day cycle for 2 months)? Or could it be something else?

NB: We're not trying to get pregnant, but it would be a 'pleasant' surprise, I guess...

Thanks in advance for the help

Big hugs