First kinda gay experience went horribly wrong - I want to overcome this

I am a 17 y/o male and I have no clue of what my sexuality is at the minute, I kinda think i'm bi. However I have a friend at college who I really like, I think he's incredibly attractive and I kinda just fell for him. He doesn't know how I feel about him at all and I couldn't tell him. I'm pretty sure he thinks i'm straight. We always talk and we're really close friends. We have a streak on Snapchat of something like 124 days. We talk on social media a lot and we've always been kinda flirty. I always take it personally even though I know that he's only messing about. Yesterday we started talking about our dicks and the size of them and stuff.. Then we started sending 'body pictures' to each other on Snapchat. He told me that he doesn't really find the male body very attractive but he liked the fact I am slightly toned. Anyway later that evening I sent him a Snapchat saying 'Send nudes' as a joke and he told me to go first so I just started sending him pictures of me hard but slightly covered under the duvet. This is when he replied with the same kind of pictures. We were both sending pictures to each other slowly revealing more and more each time but then he asked if he could see my dick. So I sent him a picture of it and he sent one back. I was so overwhelmed at the time.. We started talking on just the chat and he said that he got himself off to the picture of my dick and that he came a lot, I did the same. We were talking about how it was weird that we were both attracted to each other's dicks and that we should try giving each other handjobs and blowjobs.. Shortly after this we both went to sleep.. I woke up the following morning and I sent him another picture of my dick to which he replied with a similar image of himself rock hard. Moving on, after we had been to college today we were talking and I had sent him another three 'dick pics' that he got off to. However after he came this time he told me that it felt really wrong and that he regretted doing it. It finally ended up with him telling me that we should stop what we're doing because it's weird. I'm kinda devastated but at the same time I would never have thought that he would have sent me pictures of his dick as I didn't think he would be that way inclined.TL;DR Me and a really close, attractive friend started sending dick pictures to each other, after he had got himself off to the pictures he told me that he felt wrong and that he regretted it. I don't really know how to overcome this any advice would be appreciated!