Orgasm caused abdominal period-like cramps

I'm 5 weeks & 1 day. I've read that it's normal, but now I'm so afraid of masturbating or even having sex! I had an orgasm last night because my sex drive is high and I got cramps after. I freaked out! Does this happen to you? I haven't been to first prenatal visit. I'm also going to be a first time mom and it's my first time pregnant so I'm being cautious with everything. Advice please.