Maybe pregnant or just hopeful?

Allison • We have one daughter who is our world! She shines bright!
Had sex cycle day 15
Currently dpo 12
Current cycle day 27
Period should start Saturday
I am still breast pumping for my 14 month old but we are down to 2-3 sessions a day. 
I have had a low grade fever 99.2-99.3 for a couple of days (that I noticed). I am extremely tired and my lower back is hurting. Thoughts?