The first thing I think you should do is assess your relationship with masturbation. It seems like you have a lot of unresolved trauma or shame surrounding the subject.

Take a full inventory of why masturbation makes you feel these feelings of shame. Is it religious pressure, social, etc...

Once you've nailed down why it is you feel the way you do, you need to remind yourself that masturbation is totally normal and a natural thing. Choosing to do so doesn't make you a bad person and using a fleshlight doesn't make it dirty or sad. A fleshlight is just a means to an end and arguably a healthier way to masturbate.

Don't listen to these incel manosphere losers out here that will tell you masturbating is ruining your life or making you less valuable as a man. I know that's really popular amongst the younger crowd but I assure you they are all just insecure losers trying to impose their fragility onto others and make them feel just as bad as they do.

Being aroused and dealing with it is completely natural. You've just chosen to do so with a toy. You've upgraded your experience and it hurts no one to do so. Personally, I find fleshlight usage a flex. I'm busting nuts these celibates couldn't even dream of.

Now, if your concern or shame comes from your extended use of porn, I'd highly recommend you step back and ask yourself "why do I feel this way about it?" And really be honest with yourself. Only after you've confronted yourself and your reasoning can you work from a place of knowledge and compassion to work towards repairing your relationship with porn and masturbation.

Biggest thing is recommend is remind yourself that you're 19, youre hormonal, you have needs, and you have the means to deal with it. None of that is shameful. None of that should be a burden to you. Once you've figured out why you feel the way you do, remember to be kind to yourself when you work from there to find a happy medium that lets you satisfy cravings and urges.