5dpo what does this mean?

Me and my partner had sex 5 days before I ovulated and then on ovulation night we had sex again 2 times and he came inside me everytime.. I'm 5dpo and I've been having bad lower back pain and I have been feeling cramps/almost a full feeling in my abdominal area it goes on and off.. and I also have a little white creamy discharge and I'm very tired and hungry all the times! & Have headaches just a lil! At 2 dpo I was 79.9 temp and 79.9 ok 3dpo and on 4dpo I was 89.2 and now I'm 79.8.. Idk why I went down ... Could I be pregnant or is it just me over thinking about it to much? Please help