Im no doc but i have been fighting hemeroids(spelling) for a few years now
Alot of what you say sounds like hemmeroids.
Theres no "nice" way to say this so ill just say it as it is for me.
When doing leg presses/squats and other big movements that i create a pushing feeling from inside down towrads my anus, the ones where a fart thats right at "the edge" will escape by mistake sometimes, coupled with the posture that encourages them to escape, the posture similar to sitting on the loo.
i must keep focus on keeping my a$$ tight or my hemmies pop out and get aggrevated, mine are level two and can come out of my body, sometimes i need to put them back in, (lovely though they, just giving you the story so you can avoid it). You probably are not that advanced yet as you will know when they out there.
MIne started with constipation. First sign was blood dripping in the bowl and all the symptoms you describe.
Do you get any sharp pains in the anus sometimes randomly in the day?
Are you constipated?
DO you sometimes feel like you need to poo but theres nothing coming out no matter how hard you push?
Do you sit for long on the loo, reading for example?
Go to a doc and let him check , its not as bad as i thought it would be, the checkup, i imagined big anal probes and it was not too invasive.
You know what hemmies are right?
But you gotta go to the doc dude, and Id say go straight to a proctologist(rectal doc), not a GP.
Seeing as you put it up here i guesse you not too shy about it, i was and delayed going for long and they got worse, had i gone sooner they would be much easier to control. But i gave up being shy/embarresed about them, i talk openly about it now.
Ive had them removed eventually but they come back!
Theres various ways of treating them depending on how advanced they are, some quite painfull some not at all so its best to go before it gets worse.
There are some risks involved with having them, so its best to get professional advice and i`d say do it ASAP. Even. if just for peace of mind
hope i helped a bit