Trouble conceiving

I am going nuts and am ready to give up. I have 3 kids already and 9 8 and 6. I made a big mistake 5.5 years ago that I really wish I could take back and got a dnc (I hate myself for it so much) it would've been 5 earlier this month. But since then I feel like I'm being punished for it since I haven't had any luck getting pregnant. My husband and I have been married for a year and an half and been trying last month I was getting faint positives but then negative and a heavy af. This cycle was 50 days last was 40 days. I just slightly started af the 24 at night (I never start at night) and it's been spotting pink. Not actual blood. (Sorry for the tmi) Any advise on what I may be able to do to concieve? I am seriously about ready to throw in the white flag.