TTC and feeling anxious

I am 31 and TTC with my 2nd child.  I have a 6 year old from a prior marriage but my partner would love to have one together.  We've been attempting for the last few months without success. I haven't been doing my BBT or anything but just trying.  However, we are concerned that he may not be fertile due to having Lupus and all the treatments he's had.  Not sure if we should keep trying a while with me doing everything I can to predict the best time or if we should consult a dr.  Any suggestions??