please help!

T Lynn
I usually always have regular cycles and never miss periods. Me and my SO have been ttc for 4 months now and have had no luck. I thought I was pregnant since I was having symptoms and my "period" was really late and it was mostly brown discharge not like my usual periods. Last month I really thought I was pregnant because I didn't have a period at all. I tested about once or twice a week and even took another one this morning. All negative. Idk what's going on and it's really bringing me down not being able to conceive and getting negative after negative.