Thin Blood, Difficulty Clotting?

I'd like to know what causes this, and is it dangerous?

I know I post alot, and, heck, have a whole ton of anxiety to deal with. Though, I actually have evidence of this problem and it is really beggining to worry me.

Since December, I have had on-and-off severe nosebleeds. They clot, kind of, but the clots don't stop the bleeding. There is also a ton of bleeding, and once one nose bleed has come they can come for days even if I just accsidently poke the outside of my nose. They are so scary to me. Luckily, I haven't had one since April-May time, so I stopped worrying.

My last blood test I had (for Thyroid) took ages to stop bleeding. I was a little confused, as it never happened before, and wondered if it was the nurse jabbing too hard. So, it stopped, and I remember my auntie gave me asprin the night before so that was probably why.

Then, today, I had another blood test. Same nurse, oddly. But it wouldn't stop bleeding for a while. It's quite an odd worry for someone who all ready has anxiety.

I was also brushing my teeth today and my gum bled. I know this isn't totally a sign, since your brush can catch your gum and all, but it bled quite alot, not simply a little red on the brush and the tooth.

I'm on a whole ton of medicine. I hope I can list it.
150mg p/d Levothyroxine
10mg Propanolo beta-blockers
15mg Cinnarizine for dizziness
20mg Omeprazole

I have finished the dosage for all bar the Thyroxine which is constant. I'm kind of on a 'take them if you need them,' period now, but I was taking them for about a month each, apart from the beta-blockers which was a week or 2. I likely took more around the time of the nosebleeds, but that was things such as ear spreays, nose drops etc because I had terrible migranes (migraines) and pressure in my head and my doctor kept perscribing them. I took some heavy-duty antibiotics then that I forgot the name of, too. But that was months ago!

It's never been this way before. I've donated blood a few times, and had no problems with them taking under a pint. It didn't even dribble, really. So why now? I just don't know if this is something I have to resolve, or can resolve. How common, how dangerous, how to stop myself worrying... Please could someone help me? : (