Having let down feeling recently & slightly crampy on & off.. tester but was negative. Could it be early pregnancy?

Sometimes during the second pregnancy you do get early symptoms of being pregnant quicker. With all that you're describing, it sounds like it is possible that you might be pregnant. Since you're considered 4 weeks pregnant when your period is due), I'd give it another four or five days and then take a test if your period doesn't make its appearance.

If you haven't miss your period date yet your feeling could be due to PMS ( premenstrual syndrome). It seems that PMS and pregnancy symptoms are very similar.

it does seem like a pregnancy sign especially the letdown feeling. do give a few more days and test it in the morning where the hcg level is the highest

It seems like early pregnancy. but wait for few more days and test again to be sure

have you missed the period date? It could be implantation cramp which is early pregnancy signs

How Long have you miss your menses? You can test it again say 3-5 days later?

I think you should wait a while more and test again.. just to be sure

Could be. Better wait a while more before confirming.