TTC while nursing a toddler/no period. When to test??

Hey guys. So I have a 20 month old that I am still nursing and I have not had a period since before I was pregnant with him. My husband and I have started trying for baby #2 and I’m just confused on when to test bc i can’t base it off my last period.

Within the last week or so I’ve had light brown discharge/spotting that came and went (implantation?) And I’ve had really dull cramps everyday. Also watery discharge?Random fatigue. Nursing my son is so uncomfortable now. I cringe when he latches on. It almost hurts. Which is something that never happened before. And I’ve had really weird dreams the last 2 nights. I’ve tested this morning and yesterday morning and both negative. Could I just be testing too early?

Also I’d like to add that i haven’t had any spotting or discharge issues, or cramps in a long long time so I can’t help to think that they’re pregnancy symptoms considering it’s happening after we started trying haha.

So idk what to do! Should I keep testing everyday or just wait it out a few weeks? Thank you!