Many Health Issues... Worried About Possible Pregnancy?

Hi everyone,
i'm new to this board so let me introduce myself... I am 21 years old, and married the love of my life in september of '03. We currently do not have any children, except for our 9 month old pomeranian named mya. I have a few health problems right now, that makes the possibility (that I have) of being pregnant a little scary. First of all I have itp, which is where your blood platelets are low, and I guess go lower for pregnant women and can cause problems. My numbers aren't that bad though, my obgyn said that they are high enough to not even worry about when that time came. But rencently, they discovered through a annual pap that I have abnormal cells and I am scheduled for a 'cryo' or something like that? Where they 'freeze' the bad cells off. I also have a 5cm ovarian cyst that switches sides regularly. Anyways, I was suppose to have the cryo done jan 18th, and my doc. Asked if I was sure I couldn't be pregnant... At first I said yes, but then realised I couldn't be 100% sure because the weekend before we used the 'withdrawal' method. (which I know isn't really a method, it was more.. Like a 'moment' thing. I am not on birth control because I was taking ortho-tri and it made me very sick.) my last period was around dec 31st/jan 1st, and i'm always 28 days. So, tomorrow would make it 5 or 6 days late..... I am figuring that right, right?? Anyways, i've been obsessing about it every since my doctor asked if I was 'sure'. They didn't do the cryo, and i'm scheduled to have it done feb 8th now. I've taken 4 preg. Tests and they've all come back negative. Tomorrow i'm suppose to go to my family doc and I think i'll ask for a blood test, just to put my mind at ease, whether yes or no. The only 'symptoms' i've had lately are very tired, strange waves of naseua (sorry about spelling), about 5 days after doing the 'deed' I had lots of clear discharge(more then normal) for a few days, and last saturday I felt as if I was getting my period with uncomfortableness and cramping (not bad though). I have been under quite a bit of stress lately, and I think I might be mentally tricking myself into thinking i'm pregnant! It would be a little sooner then my husband & I would have liked, but it would still be a blessing. However, those health problems I have make me very worried! I wanted to wait until they were , at least for the most part taken care of. What does everyone here think?? I would appreciate any comments!!! Thanks everyone!! ---- ash