Clomid can negatively affect uterine lining *and* it often creates hostile cervical mucus, so it's really not a great choice if you don't need help ovulating. I was on clomid and femara, the femara is much better for fertility, IMO, because it doesn't cause the lining and cervical mucus issues that clomid often causes, and it's more likely to only send out one mature egg each cycle. (Clomid has about a 10% risk of twins.)
If you've been TTC 6 months or more with well timed intercourse (once or twice in a fertile period), it's not out of the question to go in and start inquiring about fertility testing. At the very least, some hormone testing for you (bloodwork), and a semen analysis for DH. Most *good* obgyn's aren't opposed to start basic testing after 6 months of TTC with good timing, if there are other issues going on, it makes sense for them to help you figure that out sooner than later.
Any ART has been associated with an increased risk of pre-e, but that doesn't really mean it's a cause/effect type thing. I think the theory is that women prone to fertility problems are more likely to have pre-e, they don't really know why but it goes back to implantation and everything. For what it's worth, with my first pregnancy our daughter was conceived naturally, I had HELLP at 23 weeks. This time, I was on femara, plus an HCG trigger (this makes you ovulate in a specific 24-40 hour time frame), and we did IUI (insemination) the cycle that I got pregnant, and I've made it 7 weeks farther (now at 30 weeks, no issues). So, I wouldn't stress too much about an increased pre-e risk with clomid/etc., just based on my experience and what I've seen of the research.
Me (29) DH (30)
#1-Olivia Caetlyn-9-28-09-9-28-09, 23+2 wks, emergency classic c-section, class I HELLP, IUGR
#2- Lucas Oliver (rainbow baby)- April 2011, 36+2 wks, HELLP and pre-e free! (lovenox and LDA pregnancy)
#3-Matthew, late October 2012...mostly normal, 37 wks, (lovenox and LDA again)
My blog: http://www.butterflies-and-rainbows.blogspot.com/