I got both the flu shot and H1N1 during my first trimester because I am in the high risk category being preg and a healthcare provider. I experienced no side effects and I am now 20 weeks.
I decided against it personally cause I heard your chances for a miscarriage are greater. Ive known people who have gotten the shot and their babies are still growing healthy inside them. I normally get a flu shot yearly (because Im a nurse) but decided against it this year...next year when im not pregnant Ill probably get it.
If I had known that when I got mine I would have waited it out and not gotten it. I got mine and did miscarry, although the baby passed a week before I got the shot, so it's not like in my situation it caused it. I got it because one person at work got the H1N1, since then, no on in my area has gotten it!
Since your in the early stages of the second trimester it's up to you. I would eager anyone who wants to get it to wait till at least the second trimester as the first trimester miscarriages are comment to begin with, you don't want to increase your chances just in case.
I got the regular flu shot with my first pregnancy, and that went fine, he's a healthy, happy 21 month old toddler. The dr's told me it was exactly like the flu shot, but after reading stuff it really isn't. It's made the same way, but not tested. It kinda scares me a little. This pregnancy I do not plan to get the flu shot, and I guess the H1N1 shot I had last time is still effective, if it wasn't I wouldn't get it at all.