Hi I Have Taken Many Pregnancy Tests Starting At 7

Hi I have taken many pregnancy tests starting at 7 days past ovulation (DPO) and at 8 dpo I got my first positive very faint. Each day the positive line progressively got darker. Was taking these tests w/ 4 hour urine hold. At 11 DPO I took a First Response 6 days sooner test same as the ones used before but this time with first morning urine. The result was MUCH lighter than just about all of the previous tests. Took another with a 4 hour urine hold and line was darker but not as dark as the previous day. This morning 12 DPO with first morning urine my result was even lighter than previous morning test. I am not able to get into my doctors or get a blood test at this time. Just need advice on if i should be concerned. I am 25 have a 3 year old and 19 month old and had a Miscarriage in between my two children. My basil body temp is still high also. Looking for any type of advice and thoughts thank you