Have Any Ideas? Infection, Lymphedema, Lymphoma???

Hi, I am a 28 yr. Old woman who is going through a bit of a scary time right now. I'm not sure what's wrong with me but i'll put all my info out here & see if anyone has any ideas... About a year and a half ago I developed some sudden pain in my left foot and after a few days it became swollen at the base of my toes and the top of my foot. That's all. After about a week or so the pain went away, but the swelling has never gone away. It's always swollen, but not all that bad. I went to my family physician and he suggested that maybe I had a stress fracture and ordered a bone scan which showed nothing. I visited the foot Dr. And she pretty much said the same thing and just suggested that the swelling would eventually go away. Almost a year later I visited the mayo clinic and the foot Dr. There seems to think that I have mild lymphedema. He ordered x-rays and an mri that showed nothing but a clear cyst in my big toe (which at the time of onset of pain was having a little crisis- my toe nail was shedding and lifted from the skin and almost came all the way off. It has since grown back but is still a little lifted and a little discolored.) anyhow, this Dr. Referred me to a vascular Dr. Who also seems to think that it's mild lymphedema but thinks that the sudden onset and pain to go with it is strange. He ordered tests to make sure that I didn't have any blood clots or anything. And a ct scan of the pelvis to make sure that I didn't have any tumors or anything. The scan came up fine, but noted that I had some slightly prominent (1cm) mesenteric lymph nodes and increased density of the central mesentery. And that findings may be due to inflammation changes, although early lymphoma could have a similar appearance. He assured me that he really didn't think I had anything to worry about, and that it is probably some sort of virus (even though I hadn't been sick), but had to refer me to a hematologist / lymphoma specialist. This Dr. Really put me through the testing with all types of blood work, urine test, another ct scan of the pelvis / abdomen and chest and a pet scan to rule out cancer / lymphoma. (by the way... These scans were done 2 months after the first ct scan) the pet scan showed no evidence of cancer or lymphomas. Bloodwork came back fine, but the ct scan showed the mesenteric lymph nodes, a few under the armpit and scattered ones here and there but none over 1 cm. And none in the front of the chest. It also showed an enlarged spleen. The only other thing that they made a comment on was that during the pet scan, my left ovary lit up a bit I guess and that I have a clear cyst on that ovary, and the radiologist said that it was probably just normal menstrual changes even though I was not menstruating. I just had a pap done and it came back fine. I feel healthy. The only thing that I have noticed in the past months is that once or twice a month I notice some aching for a day or so in my lower abdominal area and maybe a little back ache. I haven't been sick at all this year. The only thing that I had going on was some pockets in my tonsils that had a lot of the white cheesy-like stuff and that was between the scans. The hematologist has scheduled another ct and pet scans in another 3 months. I visited my vascular Dr. The other day and he is referring me to an infectious disease Dr. To see about viruses or whatever. Any ideas that anyone would like to share would be greatly appreciated. I'm just really worried.
Thanks,
susan-lynn