TTC whilst breastfeeding help!

I have no idea if I could be pregnant and if it's just taking a while to test positive (first pregnancy tested positive on cd30) or if I'm just hanging on in desperate hope. What do you think? Symptoms have all been there over the last couple of weeks but I'm not even sure if I ovulated as I'm still breastfeeding my 1yr old and not had a period. I've had 2 negative tests in the last 10 days so had given up hope but can't understand why my bbt is still elevated. I was using my old thermometer up until Feb 16th but a new bbt one since Feb 17th. Am I just being unrealistic, do you think theres a chance? Also I randomly started using Clearblue Advanced Digital OPK on Feb 11th with a low reading that then read high on 12th, and either high or

peak on 13th and 16th (not sure if I read it right). Don't know if it's accurate or not if you can't put in a last period date.