Am not able to stay hard; is this flatline?

Hello! I am currently on day 48 and extremely proud of that fact. During this time I have had two episodes of viewing porn for a very short amount of time but then quickly removing myself from the situation. I have been doing well up until around a week and half ago. I have been active with my girlfriend and it has been great so far. I feel less guilt and we have been having fun sexually. However, I am recently having issues getting erections and maintaining erections. This is causing me fear and I know people say that it is part of the process but I am worried. Is there anyway to cope with this? Is this flatline or am I having straight up ED. I have experienced PIED (i think before) but I have been on a fairly long streak an am now experiencing issues? Please respond with opinions and advice, thanks!