Confused

My period is "technically" only 2 days "late" (this is my 2nd period since my son was born 15 months ago, i just weaned him). It is cycle day 35. I got a faint positive 3 days ago, and have gotten a mix of faint positives and negatives since. Obviously all at different times of the day, and a couple different brands. My 1st positive test was a first repsonse. HOWEVER. My line is NOT getting any darker! Im wanting that solid line that you don't have to squint or question. I started testing right at the 30 day mark so is it possible i ovulated later than the app predicted and i got it asap with the most sensitive test possible so it might take longer to show that strong line? Am i over reaching? If the line isnt stronger after 3 days, its probably not good right? I have an appointment next week, but 🥺🤷‍♀️