Period question - WARNING - those who can't handle natural bodily functions/mechanisms of the female body please steer clear?

I already warned pansies to steer clear from my question, therefore, I will not apologize for any "gross stuff" that I will be explaining or describing... I just got my period this morning, and I put my tampon in. Tonight when I went to take my tampon out I noticed there was a bit more blood than usual. When I wiped I saw a bloody glob thing on the toilet paper. At first I thought "Oh, it's a blood clot, no big deal" but then realized it was a long narrow rolled up thing, and at one end of it, it was white/transparent - so not a blood clot I don't think - I put it on a clean paper towel got some gloves and unrolled it, wiped the blood off and it was actually a clear firm piece of fleshy material. I've never experienced this before. I made an appointment with a gynecologist JUST IN CASE (I am not freaking out - please do not respond to this question with patronizing or condescending comments telling me to "calm down" or anything of that nature - I assure you I am calm) However, I am currently attending university with a little over 30,000 students and only 3 gynecologists on campus, therefore my appointment will not be for another two and a half weeks. In the meantime, I thought maybe I could get some thoughts on this. I looked online and did some research and the most common thing I found is a miscarriage or just tissue from the uterine lining being shed during the period or something. facts about me that might be relevant: - I'm 21 - got my period at 11 - have had blood clots, but not this - there is a very high rate of miscarriage on my mom's side of the family - nearly every woman (my mom, grandmother, sister, my niece, my aunt, & her daughters) - I am living with my boyfriend of four years, we've been living together for about two now - we have sex weekly, or bi-weekly - I am on birth control - I do smoke (obviously I know it's unhealthy - no need to inform me pls)