Advice ??

My period was due 2/11 and it’s currently 5 days late, I took a total of 8 test since 2/11 and all came back faint positives. They’re ordered from oldest to newest (bottom to top) and my hcg was 11 on 2/12 and 10 as of 2/15, is this normal..?? Ive experienced a chemical pregnancy back in November and I’m thinking it may be the same outcome, it’s seems as though the lines keep getting lighter.. any advice..?? Is any of this normal..??