What is going on?!?! Thoughts please 🙏

l've done lots of pregnancy tests today which are all positive however I'm questioning if I really am.

I got a 'period' or so I thought 14 days ago. I've had really bad back pain since Friday (so three days. This is across my lower back in line with my pelvis. My back has been playing up since my pregnancy. As I needed letrozole to fall pregnant with my son I took some days 2-5 to see if I was to ovulate. I have also had light bleeding for the last three days - this started late Friday night. Nothing is going to my undies, often pink or red in colour. Not always when I wipe. No clots. I have done pregnancy and ovulation tests today which all come back positive. I've done clearblue, first response and cheap ones. I've also done a digital which says

1-2 weeks.

Am I having a miscarriage, something else going on or pregnant?

I will go to the doctor but can't for a few days.

Backstory- I'm 9 months postpartum after delivering a healthy baby at 33 weeks weight 1.7kg. We had to use letrozole to fall pregnant and it took 2 years.