Test lines

Hey girls! I am 5 weeks today and so confused. I had a blighted ovum 2 yrs ago and have been tryi g since. I had no cramping or bleeding with that time, I just went in for my 8 week appt and they told me so I had a d&c. During that pregnancy though my pregnancy test lines showed up right away from the start and continued to get very dark. This time around it takes about a minute to show up clearly and hasn't got a lot darker at all. The control line is still way darker. I have had mild cramps throughout the day for the last couple days but no bleeding. I just feel like my test lines should be really dark by now and they aren't much darker than the first one I took at 3 weeks 5 days. Should I be worried? I have my first appt/us on 4/22 at 7 weeks 1 day. Advice please!