What to do...

So my husband and I had our son last January... He passed away from SIDS in March.. it was devastating not only for us but for our 3 year old daughter... our original plan was to have one and try for another right away. After everything we decided to hold off. In June-July we decided we wanted to begin trying again... I feel like nothing works though...tracking leads to irregular cycles and when I tried fertal aide in November-December it completely stopped my cycle. Here I am middle of January and haven't had a period since october... I've taken multiple tests all negative... I'm just so lost on what to do.... any ideas???