I am sorry to read of your discomfort. I would like to offer you a somewhat different perspective than the previous expert. Absolutely, he is correct in that if you have a family history of fissures or Crohn's disease you should have examinations by a gasteroenterologist.
Please understand that I can not state with any certainty what anything is online, all I can offer is my best educated guess based upon what you wrote.
I am somewhat concerned about the "red streaking" that you mentioned. If it was a fungus, I would have expected the clotrimazole to have cleared it up. Red streaks can be a sign of a bacterial infection, one that is starting to spread within the body, especially if the streaks are getting worse.
If you still have these, and your doctor has not seen you since he first prescribed the clotrimazole, I would, were I you, return to him for a re-evaluation, just to make sure this is not something bacterial and not fungal. If its bacterial, you would need oral antibiotics to treat it. You may need a stronger anti fungal as well, if this is not bacterial. Points against it being bacterial are that you seem otherwise well; infections that can cause a streak can be accompanied by fever and malaise...but not always.
Here is some more information: while this page is meant for parents of children, the information upon it regarding infections applies equally to adults. : http://www.cpnonline.org/CRS/CRS/pa_infectio_hhg.htm
Meanwhile, for comfort, hot soaks to the area can help. But I do suggest...strongly...a doctors visit as untreated bacterial infections can result in horrid complications.
I hope I was able to help, and that you feel better soon.