Need help!

[GirlAfraid23]

Today 11:56 SpongeCake23

Something happened at 4am last night that really scared me (exactly the same thing happened on Monday night about 2am) I got up to go to the toilet, felt my heart rate go up a little bit and pounding a bit harder than usual, which is normal straight from a deep sleep and then did what I needed to do in the bathroom and went and got back into bed.
I then started straight away feeling strange when I laid down on my side, after a few seconds, the feeling rushed over me, like feeling a bit faint and weird but while laying down. I can't explain it.
Then my heart started up, probably about 130/140 BPM and I could feel it in my head and everything.
I got up panicking and felt weirdly faint and lightheaded again. I told my partner how I felt and he said to lay down. So I did and my heart was still pounding away at about 150, maybe less or more I don't know as I didn't measure it. But it was definitely harder and faster than usual. Then it gradually slowed down as I was laying on my back.
I'm so afraid there's really something wrong with me.
I'm on my period at the moment too.

[nomorepanic]

I see you posted on Mumsnet as well - you have some good answers there.

[GirlAfraid23]

I did, but I'd like some answers on here too.

[Aaahhfreakout]

The good news is you said your heart "gradually" slowed down. Heart arrhythmias start and stop suddenly therefore it's highly likely at least some -- and possibly all -- of the experience was anxiety as that has a gradual slowdown.

The question of if there was something else other than anxiety at work is not something we can answer easily here. Naturally, a check up at a doctor should be done if you think it was more than this.